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Sample records for larval plutella xylostella

  1. Tissue-Specific Transcriptome Profiling of Plutella Xylostella Third Instar Larval Midgut

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    Wen Xie, Yanyuan Lei, Wei Fu, Zhongxia Yang, Xun Zhu, Zhaojiang Guo, Qingjun Wu, Shaoli Wang, Baoyun Xu, Xuguo Zhou, Youjun Zhang

    2012-01-01

    Full Text Available The larval midgut of diamondback moth, Plutella xylostella, is a dynamic tissue that interfaces with a diverse array of physiological and toxicological processes, including nutrient digestion and allocation, xenobiotic detoxification, innate and adaptive immune response, and pathogen defense. Despite its enormous agricultural importance, the genomic resources for P. xylostella are surprisingly scarce. In this study, a Bt resistant P. xylostella strain was subjected to the in-depth transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes in the P. xylostella larval midgut.Using Illumina deep sequencing, we obtained roughly 40 million reads containing approximately 3.6 gigabases of sequence data. De novo assembly generated 63,312 ESTs with an average read length of 416bp, and approximately half of the P. xylostella sequences (45.4%, 28,768 showed similarity to the non-redundant database in GenBank with a cut-off E-value below 10-5. Among them, 11,092 unigenes were assigned to one or multiple GO terms and 16,732 unigenes were assigned to 226 specific pathways. In-depth analysis indentified genes putatively involved in insecticide resistance, nutrient digestion, and innate immune defense. Besides conventional detoxification enzymes and insecticide targets, novel genes, including 28 chymotrypsins and 53 ABC transporters, have been uncovered in the P. xylostella larval midgut transcriptome; which are potentially linked to the Bt toxicity and resistance. Furthermore, an unexpectedly high number of ESTs, including 46 serpins and 7 lysozymes, were predicted to be involved in the immune defense.As the first tissue-specific transcriptome analysis of P. xylostella, this study sheds light on the molecular understanding of insecticide resistance, especially Bt resistance in an agriculturally important insect pest, and lays the foundation for future functional genomics research. In

  2. Morphological Characteristics of P. xylostella Granulovirus and Effects on Its Larval Host Diamondback Moth Plutella xylostella L. (Lepidoptera, Plutellidae

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    A. Dezianian

    2010-01-01

    Full Text Available Problem statement: Diamondback moth, Plutella xylostella L. (Lepidoptera, Plutellidae is the most destructive insect pest of cruciferous plants throughout the world which become resistant to wide range of chemical pesticides. PxGV is known as an effective factor on diamondback moth larval mortality. Approach: Some morphological characteristics, viral DNA isolation and Restriction Endonuclease (REN analysis of P. xylostella granulovirus and its effects of different concentrations on its larval host Diamondback Moth P. xylostella, were studied. Results: Taiwanian isolate confirmed due to restriction pattern and genome size of PxGV Taiwanian isolate which was compared with PxGV isolates reported earlier. PxGV originally isolated in Taiwan has capsules that are ovocylindrical with a mean size of 272.84±12 by 148.27±19 nm. The virions are 168.44±16±29.57±12 nm. Results from pathogenicity test of the granulovirus to DBM using the leaf disc method shows that first, second and third instars of P. xylostella were significantly susceptible to infection by PxGV. Older larvae were less susceptible to PxGV than younger larvae with the same virus concentration. The LC50 for second instar larvae was 1.39±106 granules mL-1. The LT50 values ranged between 3.813-6.946, 4.965-9.743 and 5145-9.407 days for first to third instars in three different concentrations, respectively. Conclusion: Its high specificity and pathogenicity to its larval host indicate that PxGV is a good candidate as an alternative biopesticide to chemical insecticides in Integrated Pest Management (IPM of P. xylostella.

  3. Toxicity of radiation-resistant strains of Bacillus thuringiensis (Berl. ) to larval Plutella xylostella (L. )

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    Jangi, M.S.; Ibrahim, H. (Faculty of Health Sciences, Universiti Kebangsaan, Malysia, Bangi, Selangor)

    1983-05-01

    A total of 24 isolates of Bacillus thuringiensis (Berliner), resistant to a ..gamma..-radiation dose of 100 krad, were screened for their toxicity to larval silkworms, Bombyxmori(L.), and 15 of them were subsequently tested for their toxicity to larval diamond-back moth, Plutella xylostella(L.). The LC/sub 50/'s of these isolates to B. mori ranged from 1.6 X 10/sup 5/ to 6.0 X 10/sup 3/ spores/mL or from 5.9 to 0.3 ..mu..g cellular protein/mL. The irradiation treatment produced isolates which were significantly more toxic to P. xylostella (LC/sub 50/ < 8.1 X 10/sup 4/ spores/mL or 3.7 ..mu..g cellular protein/mL) and/ or less toxic to B. mori (LC/sub 50/ > 2.3 X 10/sup 4/ spores/mL or 1.0 ..mu..g cellular protein/mL) than the parent commercial strain.

  4. Silencing of ecdysone receptor, insect intestinal mucin and sericotropin genes by bacterially produced double-stranded RNA affects larval growth and development in Plutella xylostella and Helicoverpa armigera.

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    Israni, B; Rajam, M V

    2017-04-01

    RNA interference mediated gene silencing, which is triggered by double-stranded RNA (dsRNA), has become a important tool for functional genomics studies in various systems, including insects. Bacterially produced dsRNA employs the use of a bacterial strain lacking in RNaseIII activity and harbouring a vector with dual T7 promoter sites, which allow the production of intact dsRNA molecules. Here, we report an assessment of the functional relevance of the ecdysone receptor, insect intestinal mucin and sericotropin genes through silencing by dsRNA in two lepidopteran insect pests, Helicoverpa armigera and Plutella xylostella, both of which cause serious crop losses. Oral feeding of dsRNA led to significant reduction in transcripts of the target insect genes, which caused significant larval mortality with various moulting anomalies and an overall developmental delay. We also found a significant decrease in reproductive potential in female moths, with a drop in egg laying and compromised egg hatching from treated larvae as compared to controls. dsRNA was stable in the insect gut and was efficiently processed into small interfering RNAs (siRNAs), thus accounting for the phenotypes observed in the present work. The study revealed the importance of these genes in core insect processes, which are essential for insect development and survival. © 2016 The Royal Entomological Society.

  5. Evaluating trap crops for diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae).

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    Badenes-Perez, Francisco R; Shelton, Anthony M; Nault, Brian A

    2004-08-01

    Potential trap crops for the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), were evaluated through a series of ovipositional preference and larval survival experiments in outdoor screenhouses in 2002 and 2003. Hosts examined as trap crops were glossy and waxy collards, Brassica oleracea L. variety acephala; Indian mustard, Brassica juncea (L.) Czern; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata. More eggs were laid on the potential trap crops, with the exception of waxy collards, than on cabbage. When P. xylostella was offered multiple hosts at the same time, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 3, 18, and 12 times greater than on cabbage, respectively. Similarly, when P. xylostella was offered a single trap crop host and cabbage, numbers of eggs laid on glossy collards, Indian mustard, and yellow rocket were 300, 19, and 110 times greater than on cabbage, respectively. Our studies suggest differences in oviposition between the potential trap crops and cabbage were likely due to host volatiles, leaf morphology and color, or a combination of these factors, rather than to total leaf areas, leaf shape, or plant architecture. Two-choice tests with a Y-tube olfactometer indicated that plant volatiles were major factors in P. xylostella host preference. The percentage larval survival from egg to pupation was 22.2% on cabbage, 18.9% on waxy collards, and 24.4% on Indian mustard, whereas survival was significantly lower on glossy collards (6.7%) and yellow rocket (0%). Based on our tests, it seems that yellow rocket may be the best candidate for use as a trap crop for P. xylostella because it is highly attractive for oviposition, but larvae do not survive on it.

  6. Response of Plutella xylostella and its parasitoid Cotesia plutellae to volatile compounds.

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    Ibrahim, Mohamed A; Nissinen, Anne; Holopainen, Jarmo K

    2005-09-01

    The effects of limonene, a mixture of limonene + carvone (1:1, v/v), and methyl jasmonate (MeJA) on diamondback moth (DBM) (Plutella xylostella L.) oviposition, larval feeding, and the behavior of its larval parasitoid Cotesia plutellae (Kurdjumov) with cabbage (Brassica oleracea L. ssp. capitata, cvs. Rinda and Lennox) and broccoli (B. oleracea subsp. Italica cv Lucky) were tested. Limonene showed no deterrent effect on DBM when plants were sprayed with or exposed to limonene, although there was a cultivar difference. A mixture of limonene and carvone released from vermiculite showed a significant repellent effect, reducing the number of eggs laid on the cabbages. MeJA treatment reduced the relative growth rate (RGR) of larvae on cv Lennox leaves. In Y-tube olfactometer tests, C. plutellae preferred the odors of limonene and MeJA to filtered air. In cv Lennox, the parasitoid preferred DBM-damaged plants with limonene to such plants without limonene. C. plutellae females were repelled by the mixture of limonene + carvone. In both cultivars, exogenous MeJA induced the emission of the sesquiterpene (E,E)-alpha-farnesene, the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and green leaf volatile (Z)-3-hexenyl acetate + octanal. The attractive effect of limonene and MeJA predicts that these two compounds can be used in sustainable plant protection strategies in organic farming.

  7. Mortality of Plutella xylostella larvae treated with Aspidosperma pyrifolium ethanol extracts Mortalidade de larvas de Plutella xylostella tratadas com extratos etanólicos de Aspidosperma pyrifolium

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    Roseane Cristina Prédes Trindade

    2008-12-01

    Full Text Available The objective of this work was to assess the effects of Aspidosperma pyrifolium ethanol extracts on cabbage moth (Plutella xylostella larvae. The ethanol extracts of the stem bark, fruits and roots of A. pyrifolium were obtained by classical phytochemical methods, and the resulting subfractions were tested on P. xylostella, using 4 and 5 mg L-1. The crude ethanol extract of the stem bark was more lethal. The alkaloid-rich aqueous subfraction derived from the stem bark extract caused 100% larval mortality at 4 mg L-1. Insecticidal activity was associated with the presence of the monoterpenoid indole alkaloids aspidofractinine, 15-demethoxypyrifoline, and N-formylaspidofractinine. These alkaloids presented excellent insecticidal properties against P. xylostella.O objetivo deste trabalho foi avaliar os efeitos dos extratos etanólicos de Aspidosperma pyrifolium sobre lagartas da traça-das-crucíferas (Plutella xylostella. Os extratos etanólicos da casca do caule, do fruto e da raiz de A. pyrifolium foram obtidos pelos métodos fitoquímicos clássicos, e as subfrações resultantes foram testadas contra P. xylostella, nas dosagens 4 e 5 mg L-1. O extrato bruto etanólico da casca do caule foi mais letal. A subfração aquosa rica em alcalóides, derivada do extrato da casca do caule, causou 100% de mortalidade larval a 4 mg L-1. A atividade inseticida foi associada à presença dos alcalóides monoterpenóides indólicos aspidofractinina, 15-demetoxipirifolina e N-formilaspidofractinin. Estes alcalóides apresentaram excelente propriedade inseticida contra P. xylostella.

  8. Behavioural responses of diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) to extracts derived from Melia azedarach and Azadirachta indica

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    Charleston, D.S.; Kfir, R.; Vet, L.E.M.; Dicke, M.

    2005-01-01

    The impact of three different doses of botanical insecticide derived from the syringa tree, Melia azedarach and the neem tree, Azadirachta indica was tested on the behaviour of the diamondback moth, Plutella xylostella (Linnaeus). Both botanical insecticides had a significant impact on larval

  9. 小菜蛾中肠氨肽酶N2在昆虫细胞中的表达%Expression of aminopeptidase N (APN2) from Plutella xylostella larval midgut in Sf9 cells

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    王俊华; 周小毛; 吴青君; 王少丽; 谢文; 陈得峰; 徐宝云; 张友军

    2012-01-01

    利用昆虫细胞-杆状病毒表达系统(Bac-to-Bac baculovirus expression system)表达获得小菜蛾Plutella xylostella(L.)中肠氨肽酶N2( aminopeptidase N,APN2)蛋白,成功建立了该蛋白在昆虫细胞中的表达体系.将对Cry1Ac毒素敏感和已产生抗性的小菜蛾中肠APN2基因插入表达载体pFAST Bac HTB中,并在草地夜蛾Spodoptera frugiperda细胞系(Sf9)中进行了重组表达.聚丙烯酰胺凝胶电泳( SDS-PAGE)及蛋白免疫印迹技术(Western-blotting)结果显示,在107 kDa处有1条特异性蛋白条带.研究表明,小菜蛾中肠APN2基因可在Sf9细胞中成功表达,这为继续研究其功能及抗性的关系奠定了基础.%Using the insect cells-Bac-to-Bac baculovirus expression system to express APN2 (aminopeptidase N) protein, the APN2 expression system in Sf9 cells was successfully established. APN2 gene from susceptible and resistant Plutella xylostella (L. ) larval midgut were inserted into pFAST Bac HTB vector, expressed in insect cells Spodoptera frugiperda (Sf9) cells, respectively, with Bac-to-Bac baculovirus expression system. A 107 kDa protein was examined and confirmed by SDS-PAGE and Western-blotting. The results showed that P. Xylostella larval midgut APN2 gene was successfully expressed in Sf9 cells which provided a foundation for further investigation on function of APN2 and its relationship with Bt resistance.

  10. Uji Kemampuan Insektisida Botanis Ekstrak Daun Gambir terhadap Hama (Plutella Xylostella. l

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    Herwita Idris

    2015-07-01

    botanis. Plutella xylostella L (Lepidoptera: Plutellidae pest control efforts. on cabbage especially generally performed with synthetic insecticides, but the above is considered less wise because, usually in the accumulation of a very high pesticide residue that is not good for health. In this issue needs to be made more sensible control measures such as the use of botanical insecticides. Gambier (Uncaria gambier, Roxb is a botanical pesticide plant material source with huge potential, because the sap gambier leaves contain alkaloids such as chemical compounds such as catechins, tannins catecu (tannin / Tannat, querchitin, flouresin and some other compounds, where the compound katechin , tannin and querchitin is anti-microbial and anti-oxidant. In connection with the research has been done on testing the ability of some leaf extracts gambier concentrations against insects Plutella xylostella .L, at the KP.  Laing Solok starting in November 2011 through Maret 2012. Research used a completely randomized design with 7 treatments and 4 replications, each treatment is the concentration of leaf extract gambier 1000, 2000, 3000, 4000, 5000, 7500 ppm and without extract (0 ppm as a control. Parameters include the observation of mortality and larvae feed volume, and long life cycle. The results showed that the leaf extract gambier has insecticidal properties are better able to influence the physiological properties as well as the hormones of insects Plutella xylostella. L. In a 5000 ppm concentration of 7500 ppm and this material can cause the death of the larval instar (II, III and IV was equal to (60.70%, 58.70%, 55.06% and (71 , 48%, 61.20%, 56.80%. Both concentrations are also able to reduce the volume of feed (27.16%, 79.19%, 12.73% and (30.77%, 84.36%, 26.49%. As well as to extend the life cycle (13.96 to 17.49 days. Keywords: Plutella xylostella. L, biological aspects, Uncaria gambier, Roxb, botanical insecticides.

  11. A single type of cadherin is involved in Bacillus thuringiensis toxicity in Plutella xylostella.

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    Park, Y; Herrero, S; Kim, Y

    2015-12-01

    Cadherins have been described as one the main functional receptors for the toxins of the entomopathogenic bacterium, Bacillus thuringiensis (Bt). With the availability of the whole genome of Plutella xylostella, different types of cadherins have been annotated. In this study we focused on determining those members of the cadherin-related proteins that potentially play a role in the mode of action of Bt toxins. For this, we mined the genome of P. xylostella to identify these putative cadherins. The genome screening revealed 52 genes that were annotated as cadherin or cadherin-like genes. Further analysis revealed that six of these putative cadherins had three motifs common to all Bt-related cadherins: a signal peptide, cadherin repeats and a transmembrane domain. From the six selected cadherins, only P. xylostella cadherin 1 (PxCad1) was expressed in the larval midgut and only the silencing of this gene by RNA interference (double-stranded RNA feeding) reduce toxicity and binding to the midgut of the Cry1Ac type toxin from Bt. These results indicate that from the whole set of cadherin-related genes identified in P. xylostella, only PxCad1 is associated with the Cry1Ac mode of action.

  12. Sublethal effects of hexaflumuron on development and reproduction of the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae)

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    Mohammad Mahmoudvand; Habib Abbasipour; Aziz Sheikhi Garian; Ali Reza Bandani

    2011-01-01

    Effects of hexaflumuron at 10% lethal concentration (LC10) and LC25 on development and reproduction parameters of the diamondback moth,Plutella xylostella (Linnaeus,1753) (Lep.:Yponomeutidae) were investigated.Estimated LC50,LC10 and LC25 values of leaf dip bioassay of hexaflumuron on the third instar larvae of the P.xylostella were 1.48,0.59 and 0.91 mg/L,respectively.Hexaflumuron decreased pupal weight in the parent generation at sublethal concentrations but in the offspring generation,this effect was not observed.Sublethal concentrations increased egg,first and second larval instar and pupa developmental time and shortened life span of adults,but did not change the third and fourth larval instars and pre-pupa developmental period.Also fecundity of females reduced significantly but hatchability of treatments and control were similar.Survival rate of pre-adult stages declined significantly at LC25 concentration.Reproduction parameters such as reproductive rate (R0) and intrinsic rate of increase in sublethal concentrations were significantly lower compared with control,but gross reproduction rate (GRR) at the LC10 concentration was increased and it could be hormoligosis.Also hexaflumuron significantly increased doubling time (Dt).We conclude that the sublethal effects of hexaflumuron might exhibit significant effects on the population dynamics of P.xylostella.

  13. Bioactivity of microencapsulated soursop seeds extract on Plutella xylostella

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    Ismael Barros Gomes

    2016-05-01

    Full Text Available ABSTRACT: The aim of this study was to evaluate the bioactivity of microencapsulated extract from the soursop seeds, Annona muricata L. ( Annonaceae , on diamondback moth, Plutella xylostela L. (Lepidoptera: Plutellidae . Microencapsulation was performed in a Mini Spray Dryer model B-290 using 50mL of ethanolic and hexanic extracts plus 150mL of ethanol and 150mL of ultrapure water, mixed with aerosil (first polymer or arabic gum (second polymer. It was possible to microencapsulate the ethanolic extract of soursop seeds only by using the polymer arabic gum at 20%. The microencapsulated extract caused significant acute toxicity (LC50=258mg L-1 and chronic effects, especially reduction of larval viability and increased larval stage. We concluded that the microencapsulation of the ethanolic extract of soursop seeds can be a viable alternative for controlling diamondback moth with possible gains for the environment.

  14. New records of natural enemies of Plutella xylostella (L.) (Lepidoptera: Plutellidae) in Pernambuco, Brazil.

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    Silva-Torres, Christian S A; Pontes, Itillio V A F; Torres, Jorge B; Barros, Reginaldo

    2010-01-01

    We report the occurrence of natural enemies of Plutella xylostela (L.) in organically farmed kale in Pernambuco, Brazil. Seven natural enemies were observed parasitizing or preying on larvae and pupae of P. xylostella--three parasitoids: Cotesia plutellae Kurdjumov (Hym.: Braconidae), Conura pseudofulvovariegata (Becker) (Hym.: Chalcididae) and Tetrastichus howardi (Olliff) (Hym.: Eulophidae), and four predators: Cheiracanthium inclusum (Hentz) (Araneae: Miturgidae), Pheidole sp.Westwood (Hym.: Formicidae), nymphs and adults of Podisus nigrispinus (Dallas) (Hem.: Pentatomidae), and one unidentified species of solitary wasp. Beyond recording these natural enemies, data on predation of P. xylostella larvae in the field and laboratory by C. inclusum are presented.

  15. Uji Efektifitas Ekstrak Daun Mengkudu Terhadap Hama Kubis Plutella xylostella L. (Lepidoptera: Plutellidae) di Laboratorium

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    Purba, Sardes

    2009-01-01

    Uji Efektifitas Ekstrak Daun Mengkudu Terhadap Hama Kubis Plutella xylostella L. (Lepidoptera: Plutellidae) di Laboratorium dibimbing oleh Ir. Marheni MP., dan Ir. Erwin Maa’aruf, MS. Selaku ketua dan anggota. Penelitian ini bertujuan untuk mengetahui efektifitas instektisida botanis Mengkudu terhadap hama kubis P.xylostella di Laboratorium. Penelitian dilaksanakan di Laboratorium PHP BPTPH Medan Johor, Sumatera Utara yang dimulai pada bulan April 2007 sampai Juli 2007. Penelitian meng...

  16. Feeding status of the parasitoid Diadegma semiclausum affects biological control of Plutella xylostella: a simulation study

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    Hemerik, L.

    2007-01-01

    Life history characteristics of the diamondback moth (DBM), Plutella xylostella, a worldwide pest on cruciferous crops, and its important natural enemy, the parasitoid Diadegma semiclausum have intensely been studied. In addition, the searching behaviour of the parasitoid and the role of foraging ex

  17. Rapid report acetamiprid resistance and cross-resistance in the diamondback moth, Plutella xylostella.

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    Ninsin, Kodwo D

    2004-09-01

    A 110-fold acetamiprid-resistant Plutella xylostella (L) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in the laboratory. The resistant strain did not show cross-resistance to chlorfluazuron or Bacillus thuringiensis subsp kurstaki Berliner, but displayed low resistance to cartap and phenthoate.

  18. RNAi-mediated knockdown of serine protease inhibitor genes increases the mortality of Plutella xylostella challenged by destruxin A.

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    Han, Pengfei; Fan, Jiqiao; Liu, Yu; Cuthbertson, Andrew G S; Yan, Shaoqiao; Qiu, Bao-Li; Ren, Shunxiang

    2014-01-01

    Destruxin A is a mycotoxin that is secreted by entomopathogenic fungi which has a broad-spectrum insecticidal effect. Previous transcript and protein profiling analysis showed that destruxin A has significant effects on the expression of serine protease inhibitor genes (serpin-2, 4, 5) in the larvae of Plutella xylostella. In the current study, we aimed to understand the role of serpins under application of destruxin A. We obtained two full-length cDNA sequences of P. xylostella serpins, named serpin-4 and serpin-5, and cloned the serpin-2 gene whose full-length has already been published. Phylogenetic analysis indicated that these two serpin genes were highly clustered with other serpins associated with the immune response in other insects. The temporal and spatial expression of serpin-2, serpin-4 and serpin-5 were determined to be the highest in the fat body and hemolymph of 4th larval stage using qRT-PCR and western blot detection techniques. RNA interference (RNAi) mediated knockdown of P. xylostella serpin genes was carried out by microinjection of double-stranded RNA (dsRNA). The expression levels of serpins decreased significantly after RNAi. Results showed that the depletion of serpins induced cecropins expression, increased phenoloxidase (PO) activity, body melanization and mortality in the larvae of P. xylostella under the same lethal concentration of destruxin A. The superimposed effects of serpins RNAi were similar with the destruxin A treatment upon mortality of P. xylostella larvae. We discovered for the first time that serpins play indispensable role in P. xylostella when challenged by destruxin A and deduced the possible function mechanism of destruxin A. Our findings are conducive to fully understanding the potential insecticidal mechanism of destruxin A and constitute a well-defined potential molecular target for novel insecticides.

  19. Antifeedant Activity and Active Ingredients Against Plutella xylostella from Momordica charantia Leaves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With the bioguided fractionation of the ethanol extracts from the leaves of Momordica charantia, we obtained two most active compounds against the feeding of the diamondback moth, Plutella xylostella larvae. The antifeedant activity of momordicine Ⅰ and momordicine Ⅱ against the second and the third instar larvae of Plutella xylostella were tested using leaf discs of cabbage in the laboratory. The results showed that momordicin Ⅰ and momordiein Ⅱ had significant antifeedant activity on the larvae of P. Xylostella, and momordicin Ⅱ was more active than momordicin Ⅰ. The concentrations for 50% antifeedant effects (AFC50) of momordicin Ⅱ against the second and the third instar larvae of P. Xylostella were 76.69 and 116.24 μg mL-1, whereas that of momordicin Ⅰ was 144.08 and 168.42 μg mL-1, respectively. In addition, momordicin Ⅰ and momordicin Ⅱ had significant inhibitive effect on the rate of weight gain and survival of P. Xylostella larvae.

  20. Cross-Resistance to Bacillus thuringiensis Toxin CryIF in the Diamondback Moth (Plutella xylostella)

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    Tabashnik, Bruce E.; Finson, Naomi; Johnson, Marshall W.; David G Heckel

    1994-01-01

    Selection with Bacillus thuringiensis subsp. kurstaki, which contains CryIA and CryII toxins, caused a >200-fold cross-resistance to CryIF toxin from B. thuringiensis subsp. aizawai in the diamondback moth, Plutella xylostella. CryIE was not toxic, but CryIB was highly toxic to both selected and unselected larvae. The results show that extremely high levels of cross-resistance can be conferred across classes of CryI toxins of B. thuringiensis.

  1. Characterization and expression of the cytochrome P450 gene family in diamondback moth, Plutella xylostella (L.).

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    Yu, Liying; Tang, Weiqi; He, Weiyi; Ma, Xiaoli; Vasseur, Liette; Baxter, Simon W; Yang, Guang; Huang, Shiguo; Song, Fengqin; You, Minsheng

    2015-03-10

    Cytochrome P450 monooxygenases are present in almost all organisms and can play vital roles in hormone regulation, metabolism of xenobiotics and in biosynthesis or inactivation of endogenous compounds. In the present study, a genome-wide approach was used to identify and analyze the P450 gene family of diamondback moth, Plutella xylostella, a destructive worldwide pest of cruciferous crops. We identified 85 putative cytochrome P450 genes from the P. xylostella genome, including 84 functional genes and 1 pseudogene. These genes were classified into 26 families and 52 subfamilies. A phylogenetic tree constructed with three additional insect species shows extensive gene expansions of P. xylostella P450 genes from clans 3 and 4. Gene expression of cytochrome P450s was quantified across multiple developmental stages (egg, larva, pupa and adult) and tissues (head and midgut) using P. xylostella strains susceptible or resistant to insecticides chlorpyrifos and fiprinol. Expression of the lepidopteran specific CYP367s predominantly occurred in head tissue suggesting a role in either olfaction or detoxification. CYP340s with abundant transposable elements and relatively high expression in the midgut probably contribute to the detoxification of insecticides or plant toxins in P. xylostella. This study will facilitate future functional studies of the P. xylostella P450s in detoxification.

  2. Bacteria abundance and diversity of different life stages of Plutella xylostella (Lepidoptera: Plutellidae), revealed by bacteria culture-dependent and PCR-DGGE methods.

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    Lin, Xiao-Li; Pan, Qin-Jian; Tian, Hong-Gang; Douglas, Angela E; Liu, Tong-Xian

    2015-03-01

    Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella.

  3. Chronic Sublethal Effects of Cantharidin on the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae

    Directory of Open Access Journals (Sweden)

    Zhengyu Huang

    2015-05-01

    Full Text Available The diamondback moth, Plutella xylostella (Linnaeus (Lepidoptera: Plutellidae, is a major pest of cruciferous vegetables worldwide. Cantharidin, a natural toxin isolated from blister beetles, has been reported to be toxic to P. xylostella. However, little is known on the chronic sublethal effects of cantharidin on this species. In this study, we assessed the changes of susceptibility, development, reproduction and other demographic parameters in both the selected P. xylostella strain (Sub, selected by LC25 cantharidin for consecutive 12 generations and the revertant strain (SubR, derived from the Sub strain without being exposed to cantharidin for 12 generations. Results revealed that the two strains maintained a relatively high-level susceptibility to cantharidin. Severe adverse effects on the population dynamics and fitness in Sub strain were observed. In addition, repeated exposure of P. xylostella to sublethal concentration of cantharidin resulted in negative effects on adult performance and deformities in adults. Although morphologically normal for individuals, the SubR strain exhibited a disadvantage in population growth rate. Our results showed that sublethal concentration of cantharidin exhibited severe negative effects on population growth for longtime. These findings would be useful for assessing the potential effects and risk of cantharidin on P. xylostella and for developing effective integrated pest management.

  4. Field Efficacy Trials of Different Pesticides against Pieris rapae and Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    Zhao; Li; Hong; Wenying; Wu; Yanjun; Wang; Yanxin; Chen; Rui; Zhang; Linying

    2014-01-01

    Field efficacy trials of different pesticides against Pieris rapae and Plutella xylostella showed that seven pesticides had certain control effects against P.rapae and P. xylostella. 240 g/L Chlorfenapyr SC had the most ideal control effect,with quick effect and long persistence,and the control effects against P. rapae and P. xylostella were 91. 96% and 95. 73% after application for 7 d,respectively. 25% Thiamethoxam WDG 3 000 times dilution had the poorest control effect,and quick effect and persistence were not ideal; the control effects against P. rapae and P. xylostella were 49. 21% and 57. 20% after application for 7 d,respectively. The remaining pesticides had good control effect against both P. rapae and P. xylostella,with certain persistence. Slight injury such as yellowing tender leaves appeared in the area treated with 50% thiocyclam SP,although the injury was reversible,it was still not recommended to use; no other treatments had adverse effects on growth of cabbage.

  5. An anionic defensin from Plutella xylostella with potential activity against Bacillus thuringiensis.

    Science.gov (United States)

    Xu, X-X; Zhang, Y-Q; Freed, S; Yu, J; Gao, Y-F; Wang, S; Ouyang, L-N; Ju, W-Y; Jin, F-L

    2016-12-01

    Insect defensins, are cationic peptides that play an important role in immunity against microbial infection. In the present study, an anionic defensin from Plutella xylostella, (designated as PxDef) was first cloned and characterized. Amino acid sequence analysis showed that the mature peptide owned characteristic six-cysteine motifs with predicted isoelectric point of 5.57, indicating an anionic defensin. Quantitative real-time polymerase chain reaction analysis showed that PxDef was significantly induced in epidermis, fat body, midgut and hemocytes after injection of heat-inactivated Bacillus thuringiensis, while such an induction was delayed by the injection of live B. thuringiensis in the 4th instar larvae of P. xylostella. Knocking down the expression of nuclear transcription factor Dorsal in P. xylostella by RNA interference significantly decreased the mRNA level of PxDef, and increased the sensitivity of P. xylostella larvae to the infection by live B. thuringiensis. The purified recombinant mature peptide (PxDef) showed higher activity against Gram-positive bacteria, with the minimum inhibition concentrations of 1.6 and 2.6 µM against B. thuringiensis and Bacillus subtilis, respectively. To our knowledge, this is the first report about an anionic PxDef, which may play an important role in the immune system of P. xylostella against B. thuringiensis.

  6. Sub-lethal effects of Vip3A toxin on survival, development and fecundity of Heliothis virescens and Plutella xylostella.

    Science.gov (United States)

    Gulzar, Asim; Wright, Denis J

    2015-11-01

    The assessment of sub-lethal effects is important to interpret the overall insecticide efficacy in controlling insect pest populations. In addition to the lethal effect, sub-lethal effects may also occur in exposed insects. Vegetative insecticidal proteins (Vips) have shown a broad spectrum of insecticidal activity against many insect pest species. In this study the sub-lethal effects of the Bacillus thuringiensis vegetative insecticidal toxin Vip3A on the development and reproduction of Heliothis virescens F. and Plutella xylostella L. were evaluated in the laboratory. The results indicated that the sub-lethal concentration of Vip3A increased the duration of the larval and pupal stages as compared with the control treatment for both species. The percent pupation and percent adult emergence were significantly lower for Vip3A-treated insects. The proportion of pairs that produced eggs and the longevity of adults were not significantly different between treatments. H. virescens and P. xylostella treated with Vip3A showed an 11 and 17 % decrease in their intrinsic rate of increase (rm) respectively compared with untreated insects. The results from this study will be helpful to develop the strategy to incorporate Vip 3A containing crops in an integrated pest management programme.

  7. Transcriptome analysis of chlorantraniliprole resistance development in the diamondback moth Plutella xylostella.

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    Qingsheng Lin

    Full Text Available BACKGROUND: The diamondback moth Plutella xyllostella has developed a high level of resistance to the latest insecticide chlorantraniliprole. A better understanding of P. xylostella's resistance mechanism to chlorantraniliprole is needed to develop effective approaches for insecticide resistance management. PRINCIPAL FINDINGS: To provide a comprehensive insight into the resistance mechanisms of P. xylostella to chlorantraniliprole, transcriptome assembly and tag-based digital gene expression (DGE system were performed using Illumina HiSeq™ 2000. The transcriptome analysis of the susceptible strain (SS provided 45,231 unigenes (with the size ranging from 200 bp to 13,799 bp, which would be efficient for analyzing the differences in different chlorantraniliprole-resistant P. xylostella stains. DGE analysis indicated that a total of 1215 genes (189 up-regulated and 1026 down-regulated were gradient differentially expressed among the susceptible strain (SS and different chlorantraniliprole-resistant P. xylostella strains, including low-level resistance (GXA, moderate resistance (LZA and high resistance strains (HZA. A detailed analysis of gradient differentially expressed genes elucidated the existence of a phase-dependent divergence of biological investment at the molecular level. The genes related to insecticide resistance, such as P450, GST, the ryanodine receptor, and connectin, had different expression profiles in the different chlorantraniliprole-resistant DGE libraries, suggesting that the genes related to insecticide resistance are involved in P. xylostella resistance development against chlorantraniliprole. To confirm the results from the DGE, the expressional profiles of 4 genes related to insecticide resistance were further validated by qRT-PCR analysis. CONCLUSIONS: The obtained transcriptome information provides large gene resources available for further studying the resistance development of P. xylostella to pesticides. The DGE data

  8. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors

    Science.gov (United States)

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    2016-01-01

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32–35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR. PMID:27668428

  9. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors.

    Science.gov (United States)

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32-35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR.

  10. Combining Steinernema carpocapsae and Bacillus thuringienis strains for control of diamondback moth (Plutella xylostella).

    Science.gov (United States)

    Yi, X; Ehlers, R U

    2006-01-01

    The diamondback moth (DBM), Plutella xylostella, is a major pest of crucifers and has developed resistance against all chemical insecticides, even against the biological insecticide Bacillus thuringiensis (Bt). Entomopathogenic nematodes (EPN) as novel biological insecticide were successfully used against DBM. We investigated the potential of Bt to enhance the virulence of EPN and the possibility to reduce the application density by exploiting synergistic effects. The interaction between different combinations of Bt and EPN were tested against early 3rd instar P. xylostella on 2 cm2 cabbage leaf discs. All of the combinations had additive effects. Synergistic results were exceptional. The result indicate that a joint application of Bt and EPN is not recommended. But alternating applications are a measure to manage resistance development against Bt.

  11. Temperature-dependent development of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) on two brassicaceous host plants

    Institute of Scientific and Technical Information of China (English)

    ALI GOLIZADEH; KARIM KAMALI; YAGHOUB FATHIPOUR; HABIB ABBASIPOUR

    2007-01-01

    The effect of temperature on the development of the Plutella xylostella(Linnaeus) (Lepidoptera: Plutellidae), was evaluated at eight constant temperatures (10, 15,20, 25, 28, 30, 32.5 and 35℃), with relative humidity of 65% and a photoperiod of 14:10(L: D) hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage,Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.

  12. Cecropins from Plutella xylostella and Their Interaction with Metarhizium anisopliae.

    Science.gov (United States)

    Ouyang, Lina; Xu, Xiaoxia; Freed, Shoaib; Gao, Yanfu; Yu, Jing; Wang, Shuang; Ju, Wenyan; Zhang, Yuqing; Jin, Fengliang

    2015-01-01

    Cecropins are the most potent induced peptides to resist invading microorganisms. In the present study, two full length cDNA encoding cecropin2 (Px-cec2) and cecropin3 (Px-cec3) were obtained from P. xylostella by integrated analysis of genome and transcriptome data. qRT-PCR analysis revealed the high levels of transcripts of Px-cecs (Px-cec1, Px-cec2 and Px-cec3) in epidermis, fat body and hemocytes after 24, 30 and 36 h induction of Metarhizium anisopliae, respectively. Silencing of Spätzle and Dorsal separately caused the low expression of cecropins in the fat body, epidermis and hemocytes, and made the P.xylostella larvae more susceptible to M. anisopliae. Antimicrobial assays demonstrated that the purified recombinant cecropins, i.e., Px-cec1, Px-cec2 and Px-cec3, exerted a broad spectrum of antimicrobial activity against fungi, as well as Gram-positive and Gram-negative bacteria. Especially, Px-cecs showed higher activity against M. anisopliae than another selected fungi isolates. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that cecropins exerted the vital morphological alterations to the spores of M. anisopliae. Based on our results, cecropins played an imperative role in resisting infection of M. anisopliae, which will provide the foundation of biological control of insect pests by using cecorpins as a target in the future.

  13. Cecropins from Plutella xylostella and Their Interaction with Metarhizium anisopliae.

    Directory of Open Access Journals (Sweden)

    Lina Ouyang

    Full Text Available Cecropins are the most potent induced peptides to resist invading microorganisms. In the present study, two full length cDNA encoding cecropin2 (Px-cec2 and cecropin3 (Px-cec3 were obtained from P. xylostella by integrated analysis of genome and transcriptome data. qRT-PCR analysis revealed the high levels of transcripts of Px-cecs (Px-cec1, Px-cec2 and Px-cec3 in epidermis, fat body and hemocytes after 24, 30 and 36 h induction of Metarhizium anisopliae, respectively. Silencing of Spätzle and Dorsal separately caused the low expression of cecropins in the fat body, epidermis and hemocytes, and made the P.xylostella larvae more susceptible to M. anisopliae. Antimicrobial assays demonstrated that the purified recombinant cecropins, i.e., Px-cec1, Px-cec2 and Px-cec3, exerted a broad spectrum of antimicrobial activity against fungi, as well as Gram-positive and Gram-negative bacteria. Especially, Px-cecs showed higher activity against M. anisopliae than another selected fungi isolates. Scanning electron microscopy (SEM and transmission electron microscopy (TEM revealed that cecropins exerted the vital morphological alterations to the spores of M. anisopliae. Based on our results, cecropins played an imperative role in resisting infection of M. anisopliae, which will provide the foundation of biological control of insect pests by using cecorpins as a target in the future.

  14. Aspectos de preferencia alimentaria de Plutella xylostella L. (Lepidoptera ; Yponomeutidae) en algunas cruciferas cultivadas

    OpenAIRE

    1998-01-01

    p.1-5 En el presente trabajo se estudiaron ciertos aspectos de la preferencia alimentaria y dinámica poblacional de larvas de Plutella xylostella sobre Brassica olerácea var. capitata, B olerácea var. sabaucla y B. pekinensis (col china). Las variedades de repollo ensayados fueron Brunswick, Cabeza de Hierro, Corazón de Buey, Crespo de Milán y Red Meteor. Se realizó un diseño de bloques al azar con seis tratamientos (5 variedades + 1 especie) y cuatro repeticiones, librado a infestación na...

  15. Purification of the insecticidal Cry2Ad protein from a Bt-isolated BRC-HZP10 strain and toxin assay to the diamondback moth, Plutella xylostella (L.).

    Science.gov (United States)

    Liao, J Y; Gao, Y Q; Wu, Q Y; Zhu, Y C; You, M S

    2015-07-13

    The present study aims to characterize the Cry2Ad toxin protein isolated from a Bacillus thuringiensis strain, BRC-HZP10, which have a potential insecticidal activity against larvae of the diamondback moth, Plutella xylostella (L.). The crude Bt toxin proteins were isolated and purified by cation exchange chromatography, then equilibrated with 0.2 M NaOH buffer, pH 4.0, followed by ultraviolet detection at 280 nm and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A refined Cry2Ad toxin protein with 88.34% purity was eventually obtained and used for a bioassay by feeding it to P. xylostella. The results showed conspicuous insecticidal activity towards P. xylostella with 50% lethal concentration of 6.84 μg/mL and 95% confidence interval of 5.77-7.91 mg/mL. At a concentration of 16.38 μg/mL, the intake of Cry2Ad protein significantly shortened the oviposition period and larval developmental duration, but significantly reduced the fecundity and egg hatchability of the population compared to those of control (without treatment with Cry2Ad protein) (P protein plays an effective role in controlling the population of P. xylostella.

  16. The diamondback moth, Plutella xylostella, specifically inactivates Mustard Trypsin Inhibitor 2 (MTI2) to overcome host plant defence

    NARCIS (Netherlands)

    Yang, L.; Fang, Zhiyuan; Dicke, M.; Loon, van J.J.A.; Jongsma, M.A.

    2009-01-01

    The mustard trypsin inhibitor family has so far only been described among cruciferous species which represent the host plants for the specialist diamondback moth (DBM), Plutella xylostella. The performance of a Dutch and Chinese strain of DBM was assessed on transgenic Arabidopsis expressing Mustard

  17. Protein tyrosine phosphatase encoded in Cotesia plutellae bracovirus suppresses a larva-to-pupa metamorphosis of the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Kim, Jiwan; Hepat, Rahul; Lee, Daeweon; Kim, Yonggyun

    2013-09-01

    Parasitization by an endoparasitoid wasp, Cotesia plutellae, inhibits a larva-to-pupa metamorphosis of the diamondback moth, Plutella xylostella. This study tested an inhibitory effect of C. plutellae bracovirus (CpBV) on the metamorphosis of P. xylostella. Parasitized P. xylostella exhibited significantly reduced prothoracic gland (PTG) development at the last instar compared to nonparasitized larvae. Expression of the ecdysone receptor (EcR) was markedly suppressed during the last instar larvae parasitized by C. plutellae. By contrast, expression of the insulin receptor (InR) significantly increased in the parasitized larvae. Microinjection of CpBV significantly inhibited the larva-to-pupa metamorphosis of nonparasitized larvae in a dose-dependent manner. Injection of CpBV also inhibited the expression of the EcR and increased the expression of the InR. Individual CpBV segments were transiently expressed in its encoded genes in nonparasitized larvae and screened to determine antimetamorphic viral gene(s). Out of 21 CpBV segments, two viral segments (CpBV-S22 and CpBV-S27) were proved to inhibit larva-to-pupa metamorphosis by transient expression assay. RNA interference of each gene encoded in the viral segments was applied to determine antimetamorphic gene(s). Protein tyrosine phosphatase, early expressed gene, and four hypothetical genes were selected to be associated with the antimetamorphic activity of CpBV. These results suggest that antimetamorphosis of P. xylostella parasitized by C. plutellae is induced by inhibiting PTG development and subsequent ecdysteroid signaling with viral factors of CpBV.

  18. [Evaluation of non-host plant ethanol extracts against Plutella xylostella population].

    Science.gov (United States)

    Wei, Hui; Hou, Youming; Yang, Guang; Fu, Jianwei; You, Minsheng

    2005-06-01

    Through establishing experimental and natural population life tables, and by using the index of population trend (1) and interference index of population control (IIPC), this paper evaluated 8 kinds of non-host plant ethanol extracts against experimental population of Plutella xylostella, and 3 kinds of these extracts and their mixture against Plutella xylostella natural population. The experimental population life table of DBM showed that the index of population trend (I) was 69. 8964 in control, and decreased dramatically to 5.3702, 4.4842, 8.0945, 11.1382, 6.8937, 6.1609, 5.5199 and 9.8052, respectively in treatments of Zanthoxylum bungeanum, Eucalyptus tereticornis, Nicotiana tabacum, Broussonetia papyrifera, Bauhinia variegata, Duranta repens, Euphorbia hirta and Camellia oleifera ethanol extracts, while the corresponding IIPC was 0.0768, 0.0642, 0.1158, 0.1594, 0.0986, 0.0881, 0.0790 and 0. 1403, respectively. The natural population life tables of DBM showed that the index of population trend (I) was 21.6232 in control, and decreased dramatically to 5.1997, 7.4160, 7. 3644 and 3.1399, respectively in treatments of the ethanol extracts of E. tereticornis, N. tabacum, C. oleifera and their mixture, while the corresponding IIPC was 0.2405, 0.3695, 0.3549 and 0.1608, respectively. All of these indicated that the test plant extracts could interfere the development of P. xylostella population significantly, and had the potential as an effective measure for controlling insect pest.

  19. Toxicity and residual control of Plutella xylostella L. (Lepidoptera: Plutellidae with Bacillus thuringiensis Berliner and insecticides Toxicidade e controle residual de Plutella xylostella L. (Lepidoptera: Plutellidae com Bacillus thuringiensis Berliner e inseticidas

    Directory of Open Access Journals (Sweden)

    Carla Pedroso de Moraes

    2012-08-01

    Full Text Available Plutella xylostella L. is the most important worldwide pest of cruciferous plants and indiscriminate use of insecticides has led to the resistance of the species to different groups. This research was conducted to compare the toxicity and persistence of two strains of Bacillus thuringiensis to P. xylostella larvae. Concentrations between 125 and 500g 100L-1 of water of the commercial products were evaluated and compared to the insect growth inhibitor diflubenzuron and to the neurotoxic pyrethroid deltamethrin. The efficacy of the insecticides was compared between treated plants kept indoor greenhouse and outdoor. Third instar larvae were more susceptible to B. thuringiensis than first instar ones. Agree and Dipel showed similar control rates of third instars until 10 days after treatment, but on the 15th day, Agree was significantly more efficient than Dipel. Both B. thuringiensis formulations showed a reduction in mortality after 10 days when the treated plants were exposed to natural weather conditions in comparison to the same treatments kept inside greenhouse. Dimilin (100g 100L-1 of water and deltamethrin (30ml of commercial product 100L-1 of water were not efficient to control third instar larvae of P. xylostella. This inefficiency cannot be attributed to a resistant population of P. xylostella since the larval population used in the experiments was not subjected to insecticide pressure, once the crop was organically cultivated all year round. The results showed that both formulations of B. thuringiensis are sound alternatives for the control of the diamondback moth in organically conducted cruciferous crops, considering the high residual control provided under subtropical weather conditions.Larvas de Plutella xylostella L. são as principais pragas de crucíferas cultivadas e o uso excessivo e indiscriminado de inseticidas tem levado a resistência da espécie para diferentes grupos de inseticidas. Este trabalho foi conduzido para

  20. Correlation between pesticide resistance and enzyme activity in the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Gong, Ya-Jun; Wang, Ze-Hua; Shi, Bao-Cai; Kang, Zong-Jiang; Zhu, Liang; Jin, Gui-Hua; Weig, Shu-Jun

    2013-01-01

    The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is one of the most important pests that has developed high pesticide resistance. The resistances of five Chinese populations of this moth, four resistant strains (from Beijing, Henan, Fujian, and Guangdong) and one susceptible strain, to five pesticides were determined, and the activities of carboxylesterase, glutathione S-transferase, and acetylcholine esterase were tested in all five populations. The correlations between pesticide resistance and enzyme activity were analyzed. The results showed that the resistance status to the five pesticides was different among the five populations. The resistance ratios of the Beijing and Henan populations to spinosad were 5.84 and 8.22, respectively, and those to beta-cypermethrin were 4.91 and 4.98, respectively. These ratios were higher than those for the Fujian and Guangdong populations. The Fujian population was more sensitive to abamectin and chlorpyrifos than the susceptible population (the resistance ratios were 0.14 and 0.91, respectively); in fact, the median lethal concentration for P. xylostella was significantly higher for chlorpyrifos than that for any of the other four pesticides. The carboxylesterase activity in P. xylostella showed positive correlations with the resistance to spinosad, beta-cypermethrin, chlorpyrifos, and abamectin, but no correlation was observed between the carboxylesterase activity and resistance to emamectin benzoate, between glutathione S-transferase activity and resistance to any of the five pesticides tested, or between acetylcholine esterase activity and any of the pesticides except for emamectin benzoate.

  1. Insecticide effect of the extract of Furcraea hexapetala (Jacq. Urban on Plutella xylostella L.

    Directory of Open Access Journals (Sweden)

    Javier Sobrino Jiménez

    2016-01-01

    Full Text Available The investigation was developed during October and November of 2012 in order to evaluate the efficacy as insecticide of the Furcraea hexapetala (Jacq. Urban (maguey extract, against Plutella xylostella L., pest of economic importance in cabbage (Brassica oleracea L. crop. The research was carried out in Abreus municipality of the Cienfuegos province by mean of laboratory assays and a field experiment in order to determine the efficacy of the natural extract of the plant on the plague, obtained from the juice of the leaves of F. hexapetala extracted in a “trapiche” (mill used to extract the juice of the stem of sugar cane.The laboratory assay was carried out “ in vitro ” using larvae of P. xylostella fed with cabbage leaves in Petri dish. A completely randomized design was used with five treatments: extract of F. hexapetala at 100, 50, 25, 12.5 % and a control with only water. In the field experiment using random block designs were evaluated the same treatments of the extract used in the laboratory assay, including a control without any aplication. The plots had 100 m2. In both laboratory assay as at field experiment, the extract of F. hexapetala increased the efficacy against P. xylostella with concentrations of 25 % or higher. The extract of F. hexapetala to 25 % was effective under laboratory and field conditions, for that reason constitutes a good candidate to use it in the control of this pest.

  2. Identification of microRNAs from Plutella xylostella larvae associated with parasitization by Diadegma semiclausum.

    Science.gov (United States)

    Etebari, Kayvan; Hussain, Mazhar; Asgari, Sassan

    2013-04-01

    MicroRNAs (miRNAs) as small non-coding RNAs play important roles in many biological processes such as development, cell signaling and immune response. Small RNA deep sequencing technology provided an opportunity for a thorough survey of miRNAs in a global key pest Plutella xylostella as well as comparative analysis of miRNA expression profile of the insect in association with parasitization by Diadegma semiclausum. Combining the deep sequencing data and bioinformatics, 235 miRNAs were identified from P. xylostella. Differential expression of host cellular miRNAs in response to parasitism was examined by making small RNA libraries from parasitized and naive second instar larvae of P. xylostella. Bantam, miR-276*, miR-10, miR-31 and miR-184 were detected as five most abundant miRNAs in both libraries and 96 miRNAs were identified that were differentially expressed after parasitization. Bantam*, miR-184 and miR-281* were significantly down-regulated and two miRNAs miR-279b and miR-2944b* were highly induced in parasitized larvae. Interestingly, high copy numbers and differential expression of several miRNA passenger strands (miRNA*) suggest their potential roles in host-parasitoid interaction. In conclusion, expression profiling of miRNAs provided insights into their possible involvement in insect immune response to parasitism and offer an important resource for further studies.

  3. Cloning, ligand-binding, and temporal expression of ecdysteroid receptors in the diamondback moth, Plutella xylostella

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    Tang Baozhen

    2012-10-01

    Full Text Available Abstract Background The diamondback moth, Plutella xylostella (L. (Lepidoptera: Plutellidae, is a devastating pest of cruciferous crops worldwide, and has developed resistance to a wide range of insecticides, including diacylhydrazine-based ecdysone agonists, a highly selective group of molt-accelerating biopesticides targeting the ecdysone receptors. Result In this study, we cloned and characterized the ecdysone receptors from P. xylostella, including the two isoforms of EcR and a USP. Sequence comparison and phylogenetic analysis showed striking conservations among insect ecdysone receptors, especially between P. xylostella and other lepidopterans. The binding affinity of ecdysteroids to in vitro-translated receptor proteins indicated that PxEcRB isoform bound specifically to ponasterone A, and the binding affinity was enhanced by co-incubation with PxUSP (Kd =3.0±1.7 nM. In contrast, PxEcRA did not bind to ponasterone A, even in the presence of PxUSP. The expression of PxEcRB were consistently higher than that of PxEcRA across each and every developmental stage, while the pattern of PxUSP expression is more or less ubiquitous. Conclusions Target site insensitivity, in which the altered binding of insecticides (ecdysone agonists to their targets (ecdysone receptors leads to an adaptive response (resistance, is one of the underlying mechanisms of diacylhydrazine resistance. Given the distinct differences at expression level and the ligand-binding capacity, we hypothesis that PxEcRB is the ecdysone receptor that controls the remodeling events during metamorphosis. More importantly, PxEcRB is the potential target site which is modified in the ecdysone agonist-resistant P. xylostella.

  4. [Repellent and antifeedant effect of secondary metabolites of non-host plants on Plutella xylostella].

    Science.gov (United States)

    Wei, Hui; Hou, Youming; Yang, Guang; You, Minsheng

    2004-03-01

    Based on the theory of co-evolution between plants and phytophagous insects, the repellent and antifeedant effect of secondary metabolites of non-host plants on diamondback moth(DBM) Plutella xylostella was studied, aimed at finding out the oviposition repellents and antifeedants of insect pests. When the ethanol extracts(Etho Exts) of Bauhinia variegata, Eucalyptus tereticornis, Euphorbia hirta, Duranta repens, Zanthoxylum bungeanum, Magnolia grandiflora, and Nicotiana tabacum were applied respectively, the oviposition repellent rates were all over 80.00%; while after forty-eight hours treatment with the Etho Exts of Euphorbia pulcherrima, Broussonetia papyrifera, Artemisia argyi, Camellia oleifera, Salix babylonica, Euphorbia hirta, Bauhinia variegata, and Setaria viridisa, the antifeedant rates of DBM larvae were all more than 80.00%.

  5. Management of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) by mating disruption

    Institute of Scientific and Technical Information of China (English)

    Qino-Jun Wu; Shu-Fa Zhang; Jin-Liang Yao; Bao-Yun Xu; Shao-Li Wang; You-Jun Zhang

    2012-01-01

    Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth,Plutella xylostella,in cabbage,Brassica oleracea var.capitata.Effectiveness was positively correlated with the MD dispenser density in the field.A density of 167 MD dispensers per ha produced an average population decrease of about 50% compared to the conventional-practice field.Significant fewer males were captured in pheromone-treated and conventional-practice fields than in the blank control field,but the difference was not significant between the pheromone-treated and conventional-practice fields.In addition,fewer eggs and larvae were observed in pheromone-treated fields.Our results suggest mating disruption coupled with minimal insecticidal supplements is a promising solution for resistance management and control of diamondback moth infestation.

  6. Insensitive Acetylcholine Receptor Conferring Resistance of Plutella xylostella to Nereistoxin Insecticides

    Institute of Scientific and Technical Information of China (English)

    CHENG Luo-gen; YU Guang; CHEN Zi-hao; LI Zhong-yin

    2008-01-01

    The combinative rate measurement of (3-[Ⅰ125] iodotyrosyl) α-bungarotoxin was applied in the analysis of the relation between nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella (L.). In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed the remarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%, respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not show visible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticide might be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.

  7. Immunosuppression induced by expression of a viral RNase enhances susceptibility of Plutella xylostella to microbial pesticides

    Institute of Scientific and Technical Information of China (English)

    Bokri Park; Yonggyun Kim

    2012-01-01

    Polydnaviruses are a group of insect DNA viruses and are characterized in their segmented genome that is located in the chromosome(s) of host wasps.A polydnavirus,Cotesia plutellae bracovirus (CpBV),encodes a viral ribonuclease (RNase) T2 in a specific segment #3 (CpBV-S3).This study tested its effect on gene expression associated with host immune responses in the diamondback moth,Plutella xylostella.Micro-injection of CpBV-S3 into nonparasitized larvae induced expression of its two encoded genes,CpBV-ORF301 (=CpBV-RNase T2) and CpBV-ORF302.In response to a bacterial challenge,four antimicrobial peptide genes (hemolin,gloverin,cecropin and lysozyme) and six phenoloxidase (PO)-associated genes (proPO-activating proteinase,PO,serine proteinase homolog and serpins 1-3) were up-regulated in their expressions.However,the transient expression of CpBV-S3 suppressed the expressions of cecropin,PO and serpin 1.Double-stranded RNA specific to the viral RNase T2 could specifically knockdown the viral gene expression and restored the three gene expressions suppressed in the larvae injected with CpBV-S3.The inhibitory activity of the viral RNase T2 on the target genes was further proven by the suppression of PO activation in response to bacterial challenge in the larvae injected with CpBV-S3.This immunosuppression by the expression of the viral RNase T2 resulted in significant increase of pathogen susceptibility ofP.xylostella against Bacillus thuringiensis or baculovirus infection.

  8. Toxicological study of Wedelia trilobata (Asteraceae) extracts as alternative control strategies for Plutella xylostella (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Junhirun, P; Pluempanupat, W; Bullangpoti, V

    2012-01-01

    The Diamondback moth (Plutella xylostella (L)) is an economically important pest in Thailand and the indiscriminant use of chemical pesticides against this pest has been responsible for environmental hazards. Present research, therefore, is trying to develop alternative strategies by using plant based-products for the control of this pest. Wedelia trilobata (L) Hitchc extracts prepared in hexane, dichloroethane, ethyl acetate and ethanol were used initially against the second instars of P. xylostella by topical application to determine the dose dependent toxicity. The highest yield of the extracts was obtained with EtOH extract followed by hexane, EtOAc and dichloroethane. However, the EtOAc extract exhibited the highest toxicity (24h-LC50 = 442.8 ppm) that became more prominent after 48 h (LC50 = 376.71 ppm). This suggests there was an increase in toxicity with the duration of exposure to the treatment. With the exception of the hexane extract, all other treatments were significantly correlated, which suggests that W. trolobata contains a varied profile of anti-insect allelochemicals that can be exploited in any integrated pest management strategy. The identification of the active ingredients is in progress.

  9. Global identification of microRNAs associated with chlorantraniliprole resistance in diamondback moth Plutella xylostella (L.)

    Science.gov (United States)

    Zhu, Bin; Li, Xiuxia; Liu, Ying; Gao, Xiwu; Liang, Pei

    2017-01-01

    The diamondback moth (DBM), Plutella xylostella (L.), is one of the most serious cruciferous pests and has developed high resistance to most insecticides, including chlorantraniliprole. Previous studies have reported several protein-coding genes that involved in chlorantraniliprole resistance, but research on resistance mechanisms at the post-transcription level is still limited. In this study, a global screen of microRNAs (miRNAs) associated with chlorantraniliprole resistance in P. xylostella was performed. The small RNA libraries for a susceptible (CHS) and two chlorantraniliprole resistant strains (CHR, ZZ) were constructed and sequenced, and a total of 199 known and 30 novel miRNAs were identified. Among them, 23 miRNAs were differentially expressed between CHR and CHS, and 90 miRNAs were differentially expressed between ZZ and CHS, of which 11 differentially expressed miRNAs were identified in both CHR and ZZ. Using miRanda and RNAhybrid, a total of 1,411 target mRNAs from 102 differentially expressed miRNAs were predicted, including mRNAs in several groups of detoxification enzymes. The expression of several differentially expressed miRNAs and their potential targets was validated by qRT-PCR. The results may provide important clues for further study of the mechanisms of miRNA-mediated chlorantraniliprole resistance in DBM and other target insects. PMID:28098189

  10. Cross-resistance and biochemical mechanisms of resistance to indoxacarb in the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Li, Dongyang; Wan, Hu; You, Hong; Li, Jianhong

    2017-08-01

    Indoxacarb belongs to a class of insecticides known as oxadiazines and is the first commercialized pyrazoline-type voltage-dependent sodium channel blocker. A moderate level of resistance to indoxacarb has evolved in field populations of Plutella xylostella from Central China. In the present study, cross-resistance, resistance stability and metabolic mechanisms of indoxacarb resistance were investigated in this moth species. A P. xylostella strain with a high level of resistance to indoxacarb was obtained through continuous selection in the laboratory. The strain showed cross-resistance to metaflumizone, beta-cypermethrin and chlorfenapyr, but no resistance to cyantraniliprole, chlorantraniliprole, abamectin, chlorfluazuron, spinosad and diafenthiuron compared with the susceptible strain. Synergism tests revealed that piperonyl butoxide (PBO) (synergistic ratio, SR=7.8) and diethyl maleate (DEF) (SR=3.5) had considerable synergistic effects on indoxacarb toxicity in the resistant strain (F58). Enzyme activity data showed there was an approximate 5.8-fold different in glutathione S-transferase (GST) and a 6.8-fold different in cytochrome P450 monooxygenase between the resistant strain (F58) and susceptible strain, suggesting that the increased activity of these two enzymes is likely the main detoxification mechanism responsible for the species' resistance to indoxacarb. These results will be helpful for insecticide resistance management strategies to delay the development of indoxacarb resistance in fields. Copyright © 2017. Published by Elsevier Inc.

  11. Biochemical Mechanism of Chlorantraniliprole Resistance in the Diamondback Moth, Plutella xylostella Linnaeus

    Institute of Scientific and Technical Information of China (English)

    HU Zhen-di; FENG Xia; LIN Qing-sheng; CHEN Huan-yu; LI Zhen-yu; YIN Fei; LIANG Pei; GAO Xi-wu

    2014-01-01

    The insecticide chlorantraniliprole exhibits good efifcacy and plays an important role in controlling the diamondback moth, Plutella xylostella Linnaeus. However, resistance to chlorantraniliprole has been observed recently in some ifeld populations. At present study, diamondback moths with resistance to chlorantraniliprole (resistant ratio (RR) was 82.18) for biochemical assays were selected. The assays were performed to determine potential resistance mechanisms. The results showed that the selected resistant moths (GDLZ-R) and susceptible moth could be synergized by known metabolic inhibitors such as piperonyl butoxide (PBO), triphenyl phosphate (TPP) and diethyl-maleate (DEM) at different levels (1.68-5.50-fold and 2.20-2.89-fold, respectively), and DEM showed the maximum synergism in both strains. In enzymes assays, a high level of glutathione-S-transferase (GST) was observed in the resistant moth, in contrast, moths that are susceptible to the insecticide had only 1/3 the GST activity of the resistant moths. The analysis of short-term exposure of chlorantraniliprole on biochemical response in the resistant strain also showed that GST activity was signiifcantly elevated after exposure to a sub-lethal concentration of chlorantraniliprole (about 1/3 LC50, 12 mg L-1) 12 and 24 h, respectively. The results show that there is a strong correlation between the enzyme activity and resistance, and GST is likely the main detoxiifcation mechanism responsible for resistance to chlorantraniliprole in P. xylostella L., cytochrome P450 monooxygenase (P450) and carboxy-lesterase (CarE) are involved in to some extent.

  12. Insecticide resistance in populations of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), from the state of Pernambuco, Brazil.

    Science.gov (United States)

    Santos, V C; de Siqueira, H A A; da Silva, J E; de Farias, M J D C

    2011-01-01

    The diamondback moth Plutella xylostella (L.) has a great economic importance in Brassicaceae crops in many parts of the world. Recurrent infestations of this pest in growing areas of Pernambuco state, Brazil, have led farmers to frequently spray their crops with insecticides. However, control failures by several insecticides have been alleged by farmers. The objective of this study was to check whether resistance to insecticides could explain these control failures in P. xylostella. Populations of P. xylostella from Pernambuco were collected between January and April 2009. The resistance ratios of P. xylostella populations were compared among five different active ingredients: abamectin, methomyl, lufenuron, indoxacarb, and diafenthiuron by leaf dipping bioassays using foliar discs of kale leaves. Mortality data were submitted to probit analysis. The P. xylostella populations showed variable response and significant resistance to one or more insecticides. The population from Bezerros County exhibited the highest resistance ratios to indoxacarb (25.3 times), abamectin (61.7 times), and lufenuron (705.2 times), when compared to the reference population. The populations from Bonito and Jupi Counties were 33.0 and 12.0 times more resistant to lufenuron and abamectin, respectively, when compared with the reference population. Resistance to methomyl was the least common, but not less important, in at least four populations. These results indicated that control failures were associated with resistance by some of the evaluated insecticides, reinforcing the need for resistance management in areas of the state of Pernambuco.

  13. DNA sequencing reveals the midgut microbiota of diamondback moth, Plutella xylostella (L. and a possible relationship with insecticide resistance.

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    Xiaofeng Xia

    Full Text Available BACKGROUND: Insect midgut microbiota is important in host nutrition, development and immune response. Recent studies indicate possible links between insect gut microbiota and resistance to biological and chemical toxins. Studies of this phenomenon and symbionts in general have been hampered by difficulties in culture-based approach. In the present study, DNA sequencing was used to examine the midgut microbiota of diamondback moth (DBM, Plutella xylostella (L., a destructive pest that attacks cruciferous crops worldwide. Its ability to develop resistance to many types of synthetic insecticide and even Bacillus thuringiensis toxins makes it an important species to study. METHODOLOGY/PRINCIPAL FINDINGS: Bacteria of the DBM larval midgut in a susceptible and two insecticide (chlorpyrifos and fipronil resistant lines were examined by Illumina sequencing sampled from an insect generation that was not exposed to insecticide. This revealed that more than 97% of the bacteria were from three orders: Enterobacteriales, Vibrionales and Lactobacillales. Both insecticide-resistant lines had more Lactobacillales and the much scarcer taxa Pseudomonadales and Xanthomonadales with fewer Enterobacteriales compared with the susceptible strain. Consistent with this, a second study observed an increase in the proportion of Lactobacillales in the midgut of DBM individuals from a generation treated with insecticides. CONCLUSIONS/SIGNIFICANCE: This is the first report of high-throughput DNA sequencing of the entire microbiota of DBM. It reveals differences related to inter- and intra-generational exposure to insecticides. Differences in the midgut microbiota among susceptible and insecticide-resistant lines are independent of insecticide exposure in the sampled generations. While this is consistent with the hypothesis that Lactobacillales or other scarcer taxa play a role in conferring DBM insecticide resistance, further studies are necessary to rule out other

  14. Susceptibility of field populations of the diamondback moth, Plutella xylostella, to a selection of insecticides in Central China.

    Science.gov (United States)

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Mao, Kaikai; You, Hong; Li, Jianhong

    2016-09-01

    The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. However, resistance to insecticides evolves following heavy and frequent use. Therefore, the insecticide resistance in field populations of P. xylostella collected from Central China from 2013 to 2014 was determined with a leaf-dipping method. Based on the results of the monitoring, P. xylostella has developed high levels of resistance to beta-cypermethrin (resistance ratio=69.76-335.76-fold), Bt (WG-001) (RR=35.43-167.36), and chlorfluazuron (RR=13.60-104.95) and medium levels of resistance to chlorantraniliprole (RR=1.19-14.26), chlorfenapyr (RR=4.22-13.44), spinosad (RR=5.89-21.45), indoxacarb (RR=4.01-34.45), and abamectin (RR=23.88-95.15). By contrast, the field populations of P. xylostella remained susceptible to or developed low levels of resistance to diafenthiuron (RR=1.61-8.05), spinetoram (RR=0.88-2.35), and cyantraniliprole (RR=0.4-2.15). Moreover, the LC50 values of field populations of P. xylostella were highly positively correlated between chlorantraniliprole and cyantraniliprole (r=0.88, P=0.045), chlorantraniliprole and spinosad (r=0.66, P=0.039), spinosad and diafenthiuron (r=0.57, P=0.0060), and chlorfenapyr and diafenthiuron (r=0.51, P=0.016). Additionally, the activities of detoxification enzymes in field populations of P. xylostella were significantly positively correlated with the log LC50 values of chlorantraniliprole and spinosad. The results of this study provide an important base for developing effective and successful strategies to manage insecticide resistance in P. xylostella.

  15. Tebufenozide resistance selected in Plutella xylostella and its cross-resistance and fitness cost.

    Science.gov (United States)

    Cao, Guangchun; Han, Zhaojun

    2006-08-01

    A susceptible strain of diamondback moth, Plutella xylostella (L.), was used to select for resistance to tebufenozide in the laboratory. After continuous selection with tebufenozide 17 times during 35 generations, a resistant strain was achieved with high resistance to tebufenozide (RR 93.8). Bioassay revealed that this strain showed high cross-resistance to abamectin (RR 35.7), methoxyfenozide (29.1) and JS118 (16.5), and a little to deltamethrin (3.9), but no obvious cross-resistance was found to cypermethrin (1.3), fipronil (1.3), trichlorfon (1.1), chlorfenapyr (1.0), phoxim (0.9) and acephate (0.8). The resistant and susceptible insects had similar development rates, but life table tests indicated that the resistant strain showed reproductive disadvantages, including decreased copulation rate, reproductivity and hatchability. When compared with the susceptible strain, the resistant insects had a relative fitness of only 0.3. This indicated that tebufenozide resistance selected under laboratory conditions had considerable fitness costs in this pest, and therefore rotational use of insecticides without cross-resistance is recommended to delay development of resistance.

  16. Inhibitory Effects of Kojic Acid on Phenoloxidase of Diamondback Moth Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-dong; LUO Wan-chun; GAO Xing-xiang; DING Qi

    2004-01-01

    The effects of kojic acid on phenoloxidase (PO) of Plutella xylostella were investigated, when it had been partially purified by 40% saturated [(NH4)2SO4] and Sephadex G-100 gel filtration. Kojic acid showed inhibitory effects on both monophenolase and o-diphenolase activity of the PO. The inhibitor concentrations leading to 50% (IC50) activity lost were estimated to be 0.07 mmol L-1 for monophenolase and 1 mmol L-1 for diphenolase, respectively. Kojic acid can also prolong the lag time of PO for oxidation of L-tyrosine. The inhibition kinetics were analyzed by Lineweaver-Burk plots and kojic acid was found to be a reversible competitive inhibitor with the Ki of 0.47 mmol L-1. The ability of kojic acid to inhibit the enzyme activity may be associated with its ability to chelate copper at the active site. In addition, the iron ion was found to shorten the lag time obviously, but have no important effect on the monophenolase activity.

  17. EFICIÊNCIA DE INSETICIDAS PARA O CONTROLE DE Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE) NA CULTURA DO REPOLHO (Brassica oleracea var. capitata) COMPARISON OF INSECTICIDE CONTROL EFFECTIVENESS OF Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE) IN CABBAGE

    OpenAIRE

    Fábio Shigeo Takatsuka; Hellen Georgia Santana; Paulo Marçal Fernandes; Cecilia Czepak; Camilo de Lelis Rocha

    2007-01-01

    O presente trabalho foi conduzido em uma área sob plantio contínuo de repolho (Brassica oleracea var. capitata) em Goianápolis - GO, no período de setembro a novembro de 1996, visando comparar inseticidas para o controle da traça-das-crucíferas (Plutella xylostella). O delineamento experimental foi em blocos ao acaso com oito tratamentos e quatro repetições. Os tratamentos u...

  18. PEMANFAATAN PESTISIDA NABATI PADA PENGENDALIAN HAMA PLUTELLA XYLOSTELLA TANAMAN SAWI (Brassica juncea L. MENUJU PERTANIAN RAMAH LINGKUNGAN

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    suhartini suhartini

    2017-05-01

    ABSTRACT The use of chemical pesticides has many negative impacts on the environment, it is necessary for the use of biological pesticide towards sustainable agriculture or environmentally friendly agriculture. In the village were encountered many types of leaves that can be used as a biological pesticide, and therefore this study aims to determine the effectiveness of pesticide plant extracts of the leaves of some plants covering the leaves of tobacco, elephantopus, yellow wood and green betel on mortality of Plutella xylostella pests in plants mustard greens (Brassica juncea L, heavy wet mustard and mustard leaf damage    This study uses a completely randomized design with the treatment of various crops as a pesticide vegetable. The treatments used 6 kinds (degree ie negative control (P0, the leaves of tobacco (P1, the leaves of elephantopus (P2, the leaves of yellow wood (P3, the leaves of greens betel (P4 and chemical pesticides as a positive control (P5 with each grade of 10 %. Parameters measured were mortality pests, heavy wet mustard greens and mustard greens leaf damage rate. The analysis was performed by one-way ANOVA.    The results showed that the extract from the leaves of tobacco (Nicotiana tabacum, the leaves of elephantopus, the leaves of yellow wood (Arcangelisia flava L. and the leaves of green betel (Piper betle Linn. With a 10 percent concentration of the extract on a variety of  leaves are not yet significant effect on mortality pests Plutella xylostella, heavy wet of mustard greens (brassica juncea l. and severity of leaf mustard greens (brassica juncea l.. The leaf extract the most influence on mortality Plutella xylostella sequential is an extract of the leaves tobacco, the leaves of greens betel, the leaves of yellow wood and the leaves of elephantopus. While the effect on weight of wet mustard greens (Brassica juncea l. in order are as follows: the leaves of yellow wood, the leaves of green betel, the leaves of elephantopus, and the

  19. Decrease in Pupation and Adult Emergence of Plutella xylostella (L. treated with Hexaflumuron Disminución en Pupación y Emergencia de Adultos de Plutella xylostella (L. tratados por Hexaflumuron

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    Mohammad Mahmoudvand

    2012-06-01

    Full Text Available The oligophagous pest Plutella xylostella (L. is a major crucifer pest in Tehran Province, Iran. Hexaflumuron is an insect growth regulator insecticide with good effects on immature insect stages. The objective of this study was to investigate the effects of two sublethal concentrations (LC10 and LC25 of hexaflumuron on some biological parameters of P. xylostella larvae, such as birth rate (b, death rate (d, finite rate of increase (λ, generation time (T, sex ratio, pupation rate, and adult emergence. Results showed that hexaflumuron decreased the total number of eggs and oviposition and post-oviposition periods, pupation, and adult emergence in the treated generation, b, and λ. Hexaflumuron also increased T, d, and the pre-oviposition period. However, sex ratio, percentage of pupation, and adult emergence in the offspring generation were not affected by hexaflumuron. Overall, these results indicated that sublethal concentrations of hexaflumuron can affect the biological parameters of P. xylostella.Plutella xylostella (L., una plaga oligofaga, es una importante plaga de crucíferas en la provincia de Teherán, Irán. Hexaflumuron, un insecticida regulador de crecimiento de insectos, tiene buenos efectos sobre estados inmaduros de insectos. El objetivo de este estudio es investigar los efectos de dos concentraciones subletales (LC10 y LC25 de hexaflumuron sobre algunos parámetros de larvas de P. xylostella tales como tasa de nacimiento (b y tasa de mortalidad (d, tasa finita de aumento (λ, tiempo de generación (T, proporción de sexos, tasa de pupación, emergencia de adultos, y algunos otros parámetros. Los resultados mostraron que hexaflumuron redujo el número total de huevos y ovipostura y períodos de post-ovipostura, pupación, y emergencia de adultos en la generación tratada, b y λ. Hexaflumuron además aumentó T, d y el período pre-ovipostura. Sin embargo, la proporción de sexos, porcentaje de pupación, y emergencia de adultos

  20. Molecular cloning and characterization of a SID-1-like gene in Plutella xylostella.

    Science.gov (United States)

    Wang, Huidong; Gong, Liang; Qi, Jiangwei; Hu, Meiying; Zhong, Guohua; Gong, Liang

    2014-11-01

    RNA interference (RNAi) signal can spread from the point where the double-stranded RNA (dsRNA) was initially applied to other cells or tissues. SID-related genes in Caenorhabditis elegans help in the spreading of this signal. However, the mechanisms of systemic RNAi are still not unveiled in insects. In this study, we cloned a full-length cDNA of sid-1-like gene, Pxylsid-1, from Plutella xylostella that contains 1,047 bp opening reading frame encoding a putative protein of 348 amino acids. This transcript is very much similar to the sil-1 in Bombyx mori (68.8%). The higher expression levels of Pxylsid-1 were found at the adult and fourth-instar stages compared to the second-instar stage with 21.48- and 10.36-fold increase, respectively. Its expression levels in different tissues were confirmed with the highest expression in the hemolymph, which showed 21.09-fold increase than the midgut; however it was lower in other tissues. The result of RNAi by feeding bacterially expressed dsRNA targeting Pxylace-1, which showed that the mRNA level of Pxylace-1 decreased by 34.52 and 64.04% after 36- and 72-h treatment, respectively. However, the mRNA level of Pxylsid-1 was not significantly induced when the Pxylace-1 was downregulated. Furthermore, we found that downregulation of Pxylsid-1 did not affect the RNAi effect of Pxylace-1. Hence, the Pxylsid-1 may not be involved in absorption of dsRNA from the midgut fluid. A further study is needed to uncover the function of Pxylsid-1.

  1. Influência de genótipos de couve (Brassica oleracea L. var. acephala DC. na biologia de Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae Influence of cabbage genotypes (Brassica oleracea L. var. acephala DC. on the biology of Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae

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    Arlindo Leal Boiça Junior

    2011-08-01

    Full Text Available Objetivou-se, com este trabalho, avaliar a influência de alguns genótipos de couve (Brassica oleracea L. var. acephala DC. no desenvolvimento de Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae. Os genótipos avaliados foram: Manteiga de Ribeirão Pires I-2620, Roxa I-919, Manteiga de São José, Manteiga de Monte Alegre, Pires 2 de Campinas, Couve Comum, Couve de Arthur Nogueira 2, Couve de Arthur Nogueira 1. Lagartas recém-eclodidas foram mantida em discos foliares de 8 cm de diâmetro para cada genótipo. Foram analisados os seguintes parâmetros: duração e viabilidade das fases larval e pupal, longevidade e fecundidade de adultos, utilizando análises paramétricas e de agrupamentos para interpretação dos dados. Observou-se um prolongamento em dias no ciclo de P. xylostella, aumento no peso de pupa e maiores valores de viabilidade e fecundidade, durante a segunda geração. O genótipo Couve de Arthur Nogueira 2 foi menos favorável ao desenvolvimento de P. xylostella nas duas gerações, e Couve Comum demonstrou maior influência negativa ao inseto na segunda geração. Manteiga de Ribeirão Pires I-2620 foi o mais suscetível nas duas gerações, agrupando com este na segunda geração Pires 2 de Campinas e Manteiga de São José.The purpose of this study was to evaluate the effect of cabbage genotypes (Brassica oleracea L. var. acephala DC. on growth of Plutella xylostella (Lepidoptera: Plutellidae. The genotypes evaluated were: Manteiga of Ribeirão Pires I-2620, Roxa I919, Manteiga of São José, Manteiga of Monte Alegre, Pires 2 of Campinas, Couve Comum, Couve of Arthur Nogueira 2, Couve of Arthur Nogueira 1. Neonate larvae were reared in 8 cm leaf discs of each genotype. The parameters evaluated were: period and viability of the larval and pupal stages, sex ratio, longevity and fecundity of adults. Parametric and Cluster analyses were used for data analysis. Overall, it was observed a developmental delay in the P

  2. Efeito de extratos aquosos de Azadirachta indica, Melia azedarach e Aspidosperma pyrifolium no desenvolvimento e oviposição de Plutella xylostella Effect of aqueous extracts of Azadirachta indica (A. Juss, Melia azedarach (L. and Aspidosperma pyrifolium (Mart. on the development and oviposition of Plutella xylostella (L. (Lepidoptera: Plutellidae

    Directory of Open Access Journals (Sweden)

    Adalci Leite Torres

    2006-01-01

    Full Text Available Foram avaliados a CL50 e o efeito de extratos aquosos de plantas na biologia, oviposição e período embrionário de Plutella xylostella L. (Lepidoptera: Plutellidae. Para determinação da CL50 foram utilizadas concentrações entre 0,03 e 0,8 % para amêndoas de Azadirachta indica (A. Juss. 0,5 e 7,0 % para casca de Aspidosperma pyrifolium (Mart. e 0,5 e 12,5 % para frutos de Melia azedarach (L., obtendo-se as CL50 de 0,06; 2,17 e 2,90%, respectivamente. Verificou-se que os extratos aquosos de todas as espécies vegetais afetaram o desenvolvimento do inseto, principalmente na fase larval. Na fase de pupa, os extratos reduziram a massa e a viabilidade. Houve deformação de adultos para os extratos de A. pyrifolium e M. azedarach e o de A. indica causou maior porcentagem. Todos os extratos possuem efeito tóxico para ovos de P. xylostella, sendo dependente do aumento da concentração. Nos extratos da casca de A. pyrifolium, do fruto de M. azedarach e da amêndoa de A. indica observa-se ação ovicida quando usados na concentração letal de lagartas de primeiro ínstar da praga. Em observações do ovo de P. xylostella com auxílio de um microscópio eletrônico de varredura, verificou-se a existência de microporos onde pode ocorrer a penetração do produto ovicida, além da constatação da textura rugosa da casca do ovo que pode reter ou fixar os extratos.The effects of aqueous extracts of plants on the biology, preference for oviposition and embryonic period of Plutella xylostella were evaluated. Concentrations between 0.03 and 0.8 % for kernel of Azadirachta indica, 0.5 and 7.0% for peel of Aspidosperma pyrifolium and 0.5 and 12.5% for fruits of Melia azedarach were used, with LC50 values of 0.06; 2.17 and 2.90%, respectively, being obtained. It was verified that the aqueous extracts of all of the appraised vegetable species affected the development of the insect, mainly in the larval phase. In the pupae phase, the extracts reduced the

  3. Degradation of acephate by Enterobacter asburiae, Bacillus cereus and Pantoea agglomerans isolated from diamondback moth Plutella xylostella (L), a pest of cruciferous crops.

    Science.gov (United States)

    Ramya, Shanivarsanthe Leelesh; Venkatesan, Thiruvengadam; Murthy, Kottilingam Srinivasa; Jalali, Sushil Kumar; Varghese, Abraham

    2016-07-01

    Acephate-degrading bacterial isolates were isolated from the larval gut of diamondback moth Plutella xylostella, a notorious pest of cruciferous crops worldwide that has developed resistance to insecticides. Partial 16S rRNA gene sequencing identified the isolates as Bacillus cereus (PX-B.C.Or), Enterobacter asburiae (PXE), and Pantoae agglomerans (PX-Pt.ag.Jor). All isolates grew on minimal media (MM) in the presence of acephate at 100 and 200 ppm, with maximum growth at 200 ppm. LC-MS analyses of spent medium showed that E. asburiae degraded acephate to methamidophos and O, O-dimethyl phosporamidate and B. cereus O,S-dimethyl to phosphorothioate but P. agglomerans to an unnamed compound. All three isolates used acephate as a source of carbon and energy for growth; however, P. agglomerans used it also as source of sulphur. Strong evidence revealed that the bacterial communities present in the gut of diamondback moth might aid in acephate degradation and play a role in the development of insecticide resistance.

  4. Effects of delayed mating on the fecundity, fertility and longevity of females of diamondback moth, Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    Xiang-Ping Wang; Yu-Ling Fang; Zhong-Ning Zhang

    2011-01-01

    The effects of delayed mating on the copulation duration, female fertility, fecundity, egg fertility, longevity and the number days alive after mating of females of diamondback moth (DBM), Plutella xylostella, were studied. When male mating was delayed, the female fertility, fecundity, egg fertility, longevity and number days alive after mating of DBM decreased, and there was a negative correlation between the age of the moth with those variables except copulation duration. When female mating was delayed, the female fertility, fecundity, percent egg fertility and number days alive after mating of DBM also decreased, but the longevity increased, which also showed a negative relationship between the age of the moth with the variables except copulation duration and longevity. When both males and females delayed mating, the female fertility and fecundity decreased; egg fertility was affected marginally, and the longevity of females increased. The moth age was negatively correlated with those variables.

  5. REPELLENT AND OVIPOSITION DETERRENT ACTIVITIES OFTHE ESSENTIAL OIL FROM MIKANIA MICRANTHA AND ITS COMPOUNDS ON PLUTELLA XYLOSTELLA

    Institute of Scientific and Technical Information of China (English)

    Mao-xinZhang; BingLing; Shao-yingChen; Guang-wenLiang; Xiong-feiPang

    2004-01-01

    Repellent and oviposition deterrent activities of the essential oil from Mikania micrantha and five volatile compounds including limonene, a-terpinene, linalool, B-caryophylene and verbenone on the diamondback moth (DBM), Plutella xylostella, was investigated in door and in net-house. The results showed that the essential oil of the M. micrantha had significant repellant effect (at flow 100-180 mL/min) and oviposition deterrent activity at dose 1020 uL/seedling for the DBM. In five volatile compounds, a-terpinene, limonene and linalool had significant effect on repellent and oviposition deterrent of the DBM moths, but verbenone and B-caryophylene, no significantly effect was observed in repellent and oviposition deterrent.

  6. Interactions Between Bt-Bioinsecticides and Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae), a Predator of Plutella xylostella (L.) (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Magalhães, G O; Vacari, A M; DE Bortoli, C P; Pomari, A F; DE Bortoli, S A; Polanczyk, R A

    2015-10-01

    Bioinsecticides are being increasingly used to protect vegetable crops against herbivores, but data on the side effects of such strategy on the third trophic level are still required. We investigated the influence of the Bacillus thuringiensis subsp. kurstaki HD-1 strain and of the commercial bioinsecticide Agree® on the biological aspects of the predator Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) when feeding on Plutella xylostella (L.) (Lepidoptera: Plutellidae)-infected larvae. On average, infected larvae were consumed more often than the non-infected larvae throughout the predator nymphal development, and no effect on nymph survival was observed. Population growth parameters (R 0, r m, and λ) resulting from the fertility life tables did not differ among treatments. The results led to the conclusion that P. nigrispinus can be used in combination with the product Agree® or the strain HD-1 for the control of P. xylostella. The combined use of these control agents helps to maintain the balance of the ecosystem and contributes for the production of food for healthy human consumption.

  7. Bioassay technique for Plutella xylostella: Leaf-dip method%小菜蛾抗药性监测方法——叶片药膜法

    Institute of Scientific and Technical Information of China (English)

    郭磊; 边全乐; 张宏军; 高希武; 梁沛

    2013-01-01

    The diamondback moth, Plutella xylostella ( L. ) , is a notorious pest insect of cruciferous vegetables. Bioassays are an important technique for insecticide resistance monitoring and for screening the effectiveness of insecticides. This paper describes in detail the extensively used leaf dipping method in the DBM bioassay so as to provide a standard bioassay method for DBM and other lepidopterous pest insects.%小菜蛾Plutella xylostella(L.)是重要的十字花科蔬菜害虫.生物测定是进行害虫抗药性监测及筛选有效防治药剂的重要技术.本文对小菜蛾的生物测定技术进行了详细总结,以期为小菜蛾等鳞翅目害虫幼虫生物测定方法的规范提供依据.

  8. 小菜蛾抗性机理及可持续防抗对策%Resistance Mechanism and Sustainable Control Countermeasures of Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    苏文敏; 徐丽; 郁东航; 郁建飞

    2016-01-01

    Plutella xylostella has become one of the most intractable and serious crop pests with high resistance level to insecticides, rapid resistance development rate and wide resistance spectrum. This paper mainly focused on the resistance distribution and research status of resistance mechanism of P. xylostella, and further discussed the sustainable prevention and control countermeasures of P. xylostella.%小菜蛾对杀虫剂的抗性水平高、抗性产生速度快、抗性谱广,已成为当前最难治和最严重的作物害虫之一,为更好地防治小菜蛾,重点论述了小菜蛾的抗性分布、抗性机理研究现状,并进一步探讨了小菜蛾可持续防抗对策。

  9. EFICIÊNCIA DE INSETICIDAS PARA O CONTROLE DE Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE NA CULTURA DO REPOLHO (Brassica oleracea var. capitata COMPARISON OF INSECTICIDE CONTROL EFFECTIVENESS OF Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE IN CABBAGE

    Directory of Open Access Journals (Sweden)

    Fábio Shigeo Takatsuka

    2007-09-01

    Full Text Available

    O presente trabalho foi conduzido em uma área sob plantio contínuo de repolho (Brassica oleracea var. capitata em Goianápolis - GO, no período de setembro a novembro de 1996, visando comparar inseticidas para o controle da traça-das-crucíferas (Plutella xylostella. O delineamento experimental foi em blocos ao acaso com oito tratamentos e quatro repetições. Os tratamentos utilizados foram: teflubenzuron, nas doses de 25 mL, 30 mL e 40 mL de produto comercial (p.c./100 L de água; chlorfenapyr, nas doses de 30 mL, 50 mL e 100 mL de p.c./100 L de água; deltamethrin, na dose de 30 mL de p.c./100 L de água; e testemunha. Para cada tratamento realizaram-se aplicações semanais após o transplantio. As avaliações foram realizadas na colheita, contando-se o número de furos causados pela traça, em cinco cabeças comerciais de repolho, tomadas ao acaso, por parcela. Pôde-se concluir que os inseticidas teflubenzuron e chlorfenapyr foram mais eficientes que deltamethrin no controle da traça-das-crucíferas P. xylostella nas doses testadas.

    PALAVRAS-CHAVE: Inseticida; traça; controle químico.

    The research was carried out in an area under continuous cabbage cropping (Brassica oleracea var. capitata in Goianápolis, Goiás State, Brazil, from September to November 1996. The aim was to compare insecticides for diamondback moth (Plutella xylostella control. The experimental design was randomized blocks with eight treatments and four replications. The treatments were teflubenzuron in the doses of 25 mL, 30 mL and 40 mL of commercial product (c.p. / 100 L of water; chlorfenapyr in the doses of 30 mL, 50 mL and 100 mL of c.p./ 100 L of water; deltamethrin in the dose of 30 mL of c.p. / 100 L of water; and control. Treatments were applied weekly

  10. Detection of carboxylesterase and esterase activity in culturable gut bacterial flora isolated from diamondback moth, Plutella xylostella (Linnaeus, from India and its possible role in indoxacarb degradation

    Directory of Open Access Journals (Sweden)

    Shanivarsanthe Leelesh Ramya

    2016-06-01

    Full Text Available Abstract Diamondback moth (DBM, Plutella xylostella (Linnaeus, is a notorious pest of brassica crops worldwide and is resistant to all groups of insecticides. The insect system harbors diverse groups of microbiota, which in turn helps in enzymatic degradation of xenobiotic-like insecticides. The present study aimed to determine the diversity of gut microflora in DBM, quantify esterase activity and elucidate their possible role in degradation of indoxacarb. We screened 11 geographic populations of DBM in India and analyzed them for bacterial diversity. The culturable gut bacterial flora underwent molecular characterization with 16S rRNA. We obtained 25 bacterial isolates from larvae (n = 13 and adults (n = 12 of DBM. In larval gut isolates, gammaproteobacteria was the most abundant (76%, followed by bacilli (15.4%. Molecular characterization placed adult gut bacterial strains into three major classes based on abundance: gammaproteobacteria (66%, bacilli (16.7% and flavobacteria (16.7%. Esterase activity from 19 gut bacterial isolates ranged from 0.072 to 2.32 µmol/min/mg protein. Esterase bands were observed in 15 bacterial strains and the banding pattern differed in Bacillus cereus – KC985225 and Pantoea agglomerans – KC985229. The bands were characterized as carboxylesterase with profenofos used as an inhibitor. Minimal media study showed that B. cereus degraded indoxacarb up to 20%, so it could use indoxacarb for metabolism and growth. Furthermore, esterase activity was greater with minimal media than control media: 1.87 versus 0.26 µmol/min/mg protein. Apart from the insect esterases, bacterial carboxylesterase may aid in the degradation of insecticides in DBM.

  11. Effects of Various Degrees of Antennal Ablation on Mating and Oviposition Preferences of the Diamondback Moth, Plutella xylostella L.

    Institute of Scientific and Technical Information of China (English)

    YAN Xi-zhong; DENG Cai-ping; SUN Xue-jun; HAO Chi

    2014-01-01

    Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth (DBM;Plutella xylostella). The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host signiifcantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed signiifcantly when less than 1/4 of both antennae were removed. However, there was a signiifcant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.

  12. Diamondback Moth, Plutella xylostella (L. in Southern Africa: Research Trends, Challenges and Insights on Sustainable Management Options

    Directory of Open Access Journals (Sweden)

    Honest Machekano

    2017-02-01

    Full Text Available The diamondback moth (DBM, Plutella xylostella, is a global economic pest of brassicas whose pest status has been exacerbated by climate change and variability. Southern African small-scale farmers are battling to cope with increasing pressure from the pest due to limited exposure to sustainable control options. The current paper critically analysed literature with a climate change and sustainability lens. The results show that research in Southern Africa (SA remains largely constrained despite the region’s long acquaintance with the insect pest. Dependency on broad-spectrum insecticides, the absence of insecticide resistance management strategies, climate change, little research attention, poor regional research collaboration and coordination, and lack of clear policy support frameworks, are the core limitations to effective DBM management. Advances in Integrated Pest Management (IPM technologies and climate-smart agriculture (CSA techniques for sustainable pest management have not benefitted small-scale horticultural farmers despite the farmers’ high vulnerability to crop losses due to pest attack. IPM adoption was mainly limited by lack of locally-developed packages, lack of stakeholders’ concept appreciation, limited alternatives to chemical control, knowledge paucity on biocontrol, climate mismatch between biocontrol agents’ origin and release sites, and poor research expertise and funding. We discuss these challenges in light of climate change and variability impacts on small-scale farmers in SA and recommend climate-smart, holistic, and sustainable homegrown IPM options propelled through IPM-Farmer Field School approaches for widespread and sustainable adoption.

  13. cDNA sequence analysis of ribosomal protein S13 gene in Plutella xylostella (Lepidoptera: Plutellidae)

    Institute of Scientific and Technical Information of China (English)

    SHAO-LIWANG; CHENG-FASHENG; CHUAN-LINGQIAO; MIYATATADASHI

    2005-01-01

    Ribosomal protein S 13 gene has been cloned and analyzed in many organisms,but there are few documents relating to insects. In this communication, the full-length cDNA sequence of ribosomal protein S 13 gene in the diamondback moth, Plutella xylostella(Lepidoptera: Plutellidae), was determined by using PCR amplification technique. The features of the ribosomal protein S 13 gene sequence were analyzed and the deduced amino acids sequence was compared with those from other insects. The results of multi-alignment of the amino acid sequences between the diamondback moth and other insect species revealed that this gene sequence is highly conserved in insects. Based on maximum likelihood method, a phylogenetic tree was constructed from 10 different species using PHYLIP software. It showed that nematode is one separate lineage and the five insect speciesbe long to another lineage, whereas those species higher than insects form the third one. The pattern of this phylogenetic tree evidently represented the evolution of different species.

  14. Optimum timing of insecticide applications against diamondback moth Plutella xylostella in cole crops using threshold catches in sex pheromone traps.

    Science.gov (United States)

    Reddy, G V; Guerrero, A

    2001-01-01

    Field trials were conducted in cabbage (Brassica oleracea var capitata), cauliflower (B oleracea var botrytis) and knol khol (B oleracea gongylodes) crops at two different locations in Karnataka State (India) to optimize the timing of insecticide applications to control the diamondback moth, Plutella xylostella, using sex pheromone traps. Our results indicate that applications of cartap hydrochloride as insecticide during a 12-24 h period after the pheromone traps had caught on average 8, 12 and 16 males per trap per night in cabbage, cauliflower and knol khol, respectively, were significantly more effective than regular insecticide sprays at 7, 9, 12 or 15 days after transplantation. This was demonstrated by estimation of the mean number of eggs and larvae per plant, the percentage of holes produced, as well as the marketable yield of the three crops at each location. A good correlation between the immature stages, infestation level, the estimated crop yield and the number of moths caught in pheromone traps was also found, indicating the usefulness of pheromone-based monitoring traps to predict population densities of the pest.

  15. Synthesis and assessment of attractiveness and mating disruption efficacy of sex pheromone microcapsules for the diamondback moth,Plutella xylostella (L.)

    Institute of Scientific and Technical Information of China (English)

    CHEN ZengLiang; FANG YuLing; ZHANG ZhongNing

    2007-01-01

    Microcapsules of sex pheromone of the diamondback moth (DBM),Plutella xylostella (Lepidoptera:Plutellidae) were synthesized through complex coacervation using gelatin and gum arabic as wall-forming materials.The encapsulated pheromone released from these microcapsules into the air was monitored over six weeks in the field.Results of a field trial show that the attractiveness of microcapsules was superior to that of rubber septa loaded with the same amount of pheromone.The mating disruption efficiency of the pheromone treatment was estimated through comparing numbers of moths captured in pheromone-baited traps placed in pheromone treatment fields and pesticide treatment fields.The estimated mating disruption efficiency of the pheromone treatments ranged from 76.94% to 98.67% during the season.This study shows that pheromone microcapsules might provide a new method for P.xylostella control.

  16. 巴豆提取物对小菜蛾生物活性研究%Study on Bioactivity of Croton tiglium Ethanol Extracts against Plutella xylostella L.

    Institute of Scientific and Technical Information of China (English)

    王海建; 钟策宏; 蒋春先; 李庆; 杨群芳

    2013-01-01

    The bioactivity of Croton tiglium ethanol extracts against Plutella xylostella L.were studied in the laboratory.The results showed that the extracts had strong antifeedant activity and growth inhibition activity against the larva,and oviposition inhibition activity against the adult of Plutella xylostella L.The bioactivity of Croton tiglium ethanol extracts against Plutella xylostella L.increased with the concentration of the extracts.The AFC50 (effective conc.causing 50 % antifeedant rate) and ACC50 (effective conc.causing 50 % growth inhibition rate) was 3.70 and 4.12 mg/mL,respectively.The AOC50 (effective conc.causing 50 % oviposition repellent rate) was (4.37 ± 0.37) mg/mL.The effect of ethand extract of Croton tiglium for contact toxic activity and stomach toxic activity against larvae of Plutella xylostella L.were not obvious.%室内测定了巴豆乙醇提取物对小菜蛾的生物活性.结果表明,巴豆乙醇提取物对小菜蛾幼虫有较强的拒食作用和生长抑制作用,对小菜蛾成虫有较强的产卵忌避作用.提取物浓度越高,作用效果越明显.巴豆乙醇提取物对小菜蛾幼虫的拒食中浓度(AFC50)和生长抑制中浓度(AGC50)分别为3.70和4.12 mg/mL.巴豆乙醇提取物对小菜蛾成虫产卵忌避中浓度(AOC50)为4.37mg/mL.巴豆乙醇提取物对小菜蛾幼虫触杀和胃毒作用不明显.

  17. Microbial control of diamondback moth, Plutella xylostella L.(Lepidoptera:Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

    Institute of Scientific and Technical Information of China (English)

    MAHAR Ali Nawaz; MUNIR Muhammad; ELAWAD Sami; GOWEN Simon Richard; HAGUE Nigel Graham Meckenzi

    2004-01-01

    Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.

  18. Identification of multiple small heat-shock protein genes in Plutella xylostella (L.) and their expression profiles in response to abiotic stresses

    OpenAIRE

    Chen, Xi’en; Zhang, Yalin

    2014-01-01

    We identify and characterize 14 small heat-shock protein (sHSP) genes from the diamondback moth (DBM), Plutella xylostella (L.), a destructive pest. Phylogenetic analyses indicate that, except for sHSP18.8 and sHSP19.22, the other 12 DBM sHSPs belong to five known insect sHSP groups. Developmental expression analysis revealed that most sHSPs peaked in the pupal and adult stages. The transcripts of sHSPs display tissue specificity with two exhibiting constitutive expression in four tested tiss...

  19. Use of Dactylopius coccus Costa (Hemiptera: Coccoidea) pigments in the detection of larvae and pupae of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae).

    Science.gov (United States)

    Goche, D; Vigueras, A L; Portillo, L; Llanderal, C

    2012-06-01

    Carmines obtained from the dye of Dactylopius coccus Costa (Hemiptera: Coccoidea) were used for the detection of larvae and pupae of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) in broccoli inflorescences. Larvae were dyed with carmine II and red cochineal, while the majority of the dyes, with the exception of carmine III and the aqueous extract, were suitable to dye pupae. In the broccoli lumps exposed to the dyes, only the verge of the stems were actually dyed, right in the position where the incision took place, an appropriate characteristic for implementing this technique for commercial use.

  20. Microbial control of diamondback moth, Plutella xylostella L. (Lepidoptera: Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

    Institute of Scientific and Technical Information of China (English)

    MAHARAliNawaz; MUNIRMuhammad; ELAWADSami

    2004-01-01

    Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.

  1. Seletividade fisiológica de inseticidas aos inimigos naturais de Plutella xylostella (L. (Lepidoptera: Plutellidae em brássicas Insecticide physiological selectivity to natural enemies of Plutella xylostella (L. (Lepidoptera: Plutellidae in Brassicae

    Directory of Open Access Journals (Sweden)

    Leandro Bacci

    2009-01-01

    Full Text Available A conservação de inimigos naturais é um componente fundamental no manejo integrado de pragas. Neste trabalho, estudou-se a seletividade de sete inseticidas usados no manejo de Plutella xylostella (L. (Lepidoptera: Plutellidae ao parasitóide Oomyzus sokolowskii (Kurdjumov (Hymenoptera: Eulophidae e aos predadores Discodon sp. (Coleoptera: Cantharidae e Lasiochilus sp. (Hemiptera: Anthocoridae. Os organofosforados metamidofós e paratiom metílico e o carbamato carbaril foram altamente tóxicos aos três inimigos naturais estudados. Dimetoato apresentou seletividade em favor do Discodon sp., na dose e subdose. O inseticida acefato apresentou alto impacto ao Discodon sp., no momento da aplicação e seu efeito foi reduzido com a metade da concentração do princípio ativo. Deltametrina apresentou seletividade à O. sokolowskii nas duas dosagens. Já permetrina foi seletiva a Lasiochilus sp., somente na subdose. Discodon sp. foi mais tolerante à dose e subdose do dimetoato e à subdose do acefato do que O. sokolowskii e Lasiochilus sp. O predador Lasiochilus sp. foi mais tolerante à dose e subdose da permetrina do que O. sokolowskii e Discodon sp. O parasitóide O. sokolowskii foi mais tolerante à dose e subdose da deltametrina do que Lasiochilus sp. e Discodon sp. Os resultados desta pesquisa foram obtidos em condições de exposição extrema, portanto indicam que os inseticidas seletivos possivelmente não serão prejudiciais aos inimigos naturais, em condições de campo.The conservation of natural enemies is a fundamental component in the integrated pest management. In this work, one studied the selectivity of seven insecticides, used in the management of Plutella xylostella (L. (Lepidoptera: Plutellidae, to the parasitoid Oomyzus sokolowskii (Kurdjumov (Hymenoptera: Eulophidae, and to the predators Discodon sp. (Coleoptera: Cantharidae and Lasiochilus sp. (Hemiptera: Anthocoridae. The organophosphates methamidophos and methyl parathion

  2. 小菜蛾高效Bt菌株的分离、生化特性及基因型鉴定%Isolation, biochemical and cry-type gene characterization of Bacillus thuringiensis strains with high toxic to Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    朱勋; 吴青君; 张友军; 刘春光; 刘岩林; 余亚军; 景伟; 薛原; 杨峰山

    2011-01-01

    The insecticidal activities of ten strains of Bacillus thuringiensis isolated from diseased Plutella xylostella ( L. )larvae were characterized. All strains caused > 80% larval mortality and the strain DBW902 had the highest insecticidal activity with an LC50 of 13.99 mg/L at 48 h. The biochemical characteristics and cry/cyt genes of each strain were determined. High insecticidal activity coincided with the detection of at least one crylA or cry2A family gene. The biochemical characteristics of the strains, DBW904, DBW93 and DBW962 were homologous to B. thuringiensis subsp.and Shandongiensis, but not the other strains. The identification of these 10 B. thuringiensis isolates with moderate to high insecticidal activity against P. xylostella is promising for the control of this pest in northeastern China.%从啥尔滨田间采集死亡小菜蛾Plutella xylostella(L.)幼虫,从中分离出10株苏云金芽孢杆菌Bacillusthuringiensis.对小菜蛾幼虫室内生物测定结果表明,各菌株对小菜蛾幼虫的死亡率均在85%以上,其中DBW902毒力最强,48 h的LC为13.99 mg/L.菌株cry/cyt基因检测表明,所有菌株均含有cry1A或cry2A基因,这与其高毒力的特性基本吻合.生化检测与分析表明,菌株DBW904、DBW93、DBW962与已报道的苏云金芽孢杆菌山东亚种B.thuringiensis subsp.shandongiensis的生化特性一致,但是其它菌株的生理生化特性与已报道菌株有区别.

  3. Low mtDNA diversity among widespread Australian diamondback moth Plutella xylostella (L.) suggests isolation and a founder effect

    Institute of Scientific and Technical Information of China (English)

    JESSLYN SAW; NANCY M. ENDERSBY; STEPHEN W. MCKECHNIE

    2006-01-01

    Populations of Australian diamondback moth (DBM) Plutella xylostella (L.), a serious pest of cruciferous crops, display extremely low levels of genetic differentiation across Australia and New Zealand sample locations, as determined previously using microsatellite markers. These data suggest high levels of contemporary gene flow that is consistent with Australian DBM being a vagile species. Here we examine Australian DBM samples for haplotype variation using the mitochondrial DNA sequences of a 257 bp fragment of the CO1 gene. We compare this variation to equivalent mtDNA sequence variation in samples from New Zealand, Kenya and Korea. Using 42 moths collected throughout Australia we show that Australian DBM have both low mtDNA haplotype and nucleotide diversities. The three Australian haplotypes detected are closely related and they cluster with the common haplotype group from Indonesia. In addition the Australian haplotype frequency distribution resembled more that from Indonesia than that from Kenya or Korea. These data are consistent with an original strong Australian/New Zealand founder effect, from a south-eastern Asian source, with subsequent continued isolation. In a single season, the frequency of PXMt01, the most common Australian haplotype, was estimated at 15 locations spread across southern Australia and New Zealand using a polymerase chain reaction BiPASA method. The PXMt01 haplotype frequency variation was heterogenous,suggesting a small degree of population isolation that was not detected using microsatellites.Differentiation was not a function of geographical distance. These data suggest transient and sporadic local colonisation events by small numbers of founding females.

  4. Common, but complex, mode of resistance of Plutella xylostella to Bacillus thuringiensis toxins Cry1Ab and Cry1Ac.

    Science.gov (United States)

    Sayyed, Ali H; Gatsi, Roxani; Ibiza-Palacios, M Sales; Escriche, Baltasar; Wright, Denis J; Crickmore, Neil

    2005-11-01

    A field collected population of Plutella xylostella (SERD4) was selected in the laboratory with Bacillus thuringiensis endotoxins Cry1Ac (Cry1Ac-SEL) and Cry1Ab (Cry1Ab-SEL). Both subpopulations showed similar phenotypes: high resistance to the Cry1A toxins and little cross-resistance to Cry1Ca or Cry1D. A previous analysis of the Cry1Ac-SEL showed incompletely dominant resistance to Cry1Ac with more than one factor, at least one of which was sex influenced. In the present study reciprocal mass crosses between Cry1Ab-SEL and a laboratory susceptible population (ROTH) provided evidence that Cry1Ab resistance was also inherited as incompletely dominant trait with more than one factor, and at least one of the factors was sex influenced. Analysis of single pair mating indicated that Cry1Ab-SEL was still heterogeneous for Cry1Ab resistance genes, showing genes with different degrees of dominance. Binding studies showed a large reduction of specific binding of Cry1Ab and Cry1Ac to midgut membrane vesicles of the Cry1Ab-SEL subpopulation. Cry1Ab-SEL was found to be more susceptible to trypsin-activated Cry1Ab toxin than protoxin, although no defect in toxin activation was found. Present and previous results indicate a common basis of resistance to both Cry1Ab and Cry1Ac in selected subpopulations and suggest that a similar set of resistance genes are responsible for resistance to Cry1Ab and Cry1Ac and are selected whichever toxin was used. The possibility of an incompletely dominant trait of resistant to these toxins should be taken into account when considering refuge resistance management strategies.

  5. Electrophysiology and behavior feedback of diamondback moth, Plutella xylostella, to volatile secondary metabolites emitted by Chinese cabbage

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The volatiles, absorbed by Porapak Q and eluted by hexane, from Chinese cabbage, Brassica campestris chinesis (L.) Makino. var. communis Tsen et Lee, have been identified as allyl isothiocyanate, Z-3-hexenyl acetate, 3,7-dimethyl-1,3,6-octatriene, 2,5-hexanediol, Z-3-hexen-1-ol, nonanol, (-myrcene, (-pinene, E-2-hexen-1-ol, D-limonene, Z-3-hexenyl propanoate, linalool, geraniol, E-4-hexen-1-ol, Z-3-hexenyl isovalerate, (-terpinene, (-caryophyllene, 3-carene and (-caryophyllene, by their mass spectra and retention times in comparison with authentic samples. The first five chemicals are the main components. All components can elicite electroantennogram (EAG) responses of diamondback moth (DBM), Plutella xylostella, in which allyl isothiocyanate and C6 alcohols and esters, i.e. Z-3-hexen-1-ol, E-2-hexen-1-ol, E-4-hexen-1-ol, Z-3-hexenyl isovalerate and 2,5-hexanediol elicite stronger EAG responses than other components, and EAG responses of female moths to them are slightly larger than those of male moths. However, EAG responses elicited by terpenes are smaller, and EAG responses from females to terpenes are smaller than those from males, but ((myrcene can evoke stronger EAG responses from both females and males. Volatiles from intact Chinese cabbage, allyl isothiocyanate, 2,5-hexanediol and Z-3-hexenyl isovalerate intensely cause DBM directional flying and landing in wind tunnel, in which volatiles from intact Chinese cabbage have the strongest activity, and the next is allyl isothiocyanate. Allyl isothiocyanate is more attractive to females than to males a bit. As for (-terpinene and other subordinate components, EAG and wind tunnel test make sure they have weak activity.

  6. 菜蛾绒茧蜂和小菜蛾对杀虫剂的敏感性及酶学特性的比较研究%Susceptibility to insecticides and enzymetic characteristics in the parasitoid Apanteles plutellae Kurdj.(Hymenoptera:Braconidae) and its host Plutella xylostella (L.)( Lepidoptera:Yponomeutidae)

    Institute of Scientific and Technical Information of China (English)

    吴刚; 江树人

    2004-01-01

    The susceptibility to insecticides in the larval parasitoid Apanteles plutellae Kurdjumov (Hymenoptera: Braconidae)and its host Plutella xylostella (L.) (Lepidoptera: Yponomeutidae),collected in Fuzhou, China, were detected using residual film and leaf-dip bioassays, respectively. The results showed that organophosphates, carbamates, pyrethroids, avermectins and fipronil were highly toxic to A. plutellae, but chlorfluazuron and Bt were not. However, A. plutellae could survive from the conventional control doses of fipronil, fenvalerate, cypermethrin and acephate if the parasitoid was left in contact with the insecticides only for short time ( 1 h). In A. plutellae, there were obvious synergisms of piperonyl butoxide ( PB), triphenyl phosphate (TPP) and diethyl maleate (DEM) on methamidophos, carbofuran, fenvalerate, cypermethrin, avermectins and fipronil, but no synergisms on chlorfluazuron were found. The synergism of PB was the highest. Acetylcholinesterase (AChE)activity could not be inhibited by PB, TPP and DEM, but strong inhibition could be found in carboxylesterase (CarE) activity by PB and TPP, and in glutathione-S-transferase (GST) activity by DEM, in vivo. The apparent Michaelis-Menten constant ( Km ),the maximal velocity (Vmax) of AChE, and the activities of CarE and GST in A. plutellae were 0.22, 2.08, 4.60 and 0.45-fold as those in P. xylostella, respectively. The bimolecular rate constants (Ki ) of AChE to methamidophos, dichlorvos and carbofuran in A. plutellae were 14.7, 10.5 and 26.0-fold as those in P. xylostella, respectively. High inhibition of AChE was found in both species when being incubated with insecticides at high temperature, especially in A. plutellae. The results indicated that the high susceptibilities to organophosphates and carbametes in A. plutellae were related to its high sensitivity of AChE to the insecticides, and the oxidative metabolism might be more effective in tolerance to insecticides than non-oxidative metabolism in A

  7. Engineering of benzylglucosinolate in tobacco provides proof-of-concept for dead-end trap crops genetically modified to attract Plutella xylostella (diamondback moth).

    Science.gov (United States)

    Møldrup, Morten E; Geu-Flores, Fernando; de Vos, Martin; Olsen, Carl E; Sun, Joel; Jander, Georg; Halkier, Barbara A

    2012-05-01

    Glucosinolates are biologically active natural products characteristic of crucifers, including oilseed rape, cabbage vegetables and the model plant Arabidopsis thaliana. Crucifer-specialist insect herbivores, like the economically important pest Plutella xylostella (diamondback moth), frequently use glucosinolates as oviposition stimuli. This suggests that the transfer of a glucosinolate biosynthetic pathway to a non-crucifer would stimulate oviposition on an otherwise non-attractive plant. Here, we demonstrate that stable genetic transfer of the six-step benzylglucosinolate pathway from A. thaliana to Nicotiana tabacum (tobacco) results in the production of benzylglucosinolate without causing morphological alterations. Benzylglucosinolate-producing tobacco plants were more attractive for oviposition by female P. xylostella moths than wild-type tobacco plants. As newly hatched P. xylostella larvae were unable to survive on tobacco, these results represent a proof-of-concept strategy for rendering non-host plants attractive for oviposition by specialist herbivores with the long-term goal of generating efficient dead-end trap crops for agriculturally important pests.

  8. The Correlation of the Presence and Expression Levels of cry Genes with the Insecticidal Activities against Plutella xylostella for Bacillus thuringiensis Strains

    Directory of Open Access Journals (Sweden)

    Ming-Lun Chen

    2014-08-01

    Full Text Available The use of Bacillus thuringiensis (Bt strains with high insecticidal activity is essential for the preparation of bioinsecticide. In this study, for 60 Bt strains isolated in Taiwan, their genotypes and the correlation of some cry genes as well as the expression levels of cry1 genes, with their insecticidal activities against Plutella xylostella, were investigated. Pulsed field gel electrophoresis (PFGE and random amplified polymorphic DNA (RAPD results revealed that the genotypes of these Bt strains are highly diversified. Also, a considerable number of the Bt strains isolated in Taiwan were found to have high insecticidal activities. Since strains that showed individual combined patterns of PFGE and RAPD exhibited distinct insecticidal activities against P. xylostella, thus, these genotypes may be useful for the identification of the new Bt strains and those which have been used in bioinsecticides. In addition, although the presence of cry2Aa1 may have a greater effect on the insecticidal activity of Bt strains in bioassay than other cry genes, only high expression level of cry1 genes plays a key role to determine the insecticidal activity of Bt strains. In conclusion, both RAPD and PFGE are effective in the differentiation of Bt strains. The presence of cry2Aa1 and, especially, the expression level of cry1 genes are useful for the prediction of the insecticidal activities of Bt strains against P. xylostella.

  9. The correlation of the presence and expression levels of cry genes with the insecticidal activities against Plutella xylostella for Bacillus thuringiensis strains.

    Science.gov (United States)

    Chen, Ming-Lun; Chen, Pin-Hsin; Pang, Jen-Chieh; Lin, Chia-Wei; Hwang, Chin-Fa; Tsen, Hau-Yang

    2014-08-19

    The use of Bacillus thuringiensis (Bt) strains with high insecticidal activity is essential for the preparation of bioinsecticide. In this study, for 60 Bt strains isolated in Taiwan, their genotypes and the correlation of some cry genes as well as the expression levels of cry1 genes, with their insecticidal activities against Plutella xylostella, were investigated. Pulsed field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) results revealed that the genotypes of these Bt strains are highly diversified. Also, a considerable number of the Bt strains isolated in Taiwan were found to have high insecticidal activities. Since strains that showed individual combined patterns of PFGE and RAPD exhibited distinct insecticidal activities against P. xylostella, thus, these genotypes may be useful for the identification of the new Bt strains and those which have been used in bioinsecticides. In addition, although the presence of cry2Aa1 may have a greater effect on the insecticidal activity of Bt strains in bioassay than other cry genes, only high expression level of cry1 genes plays a key role to determine the insecticidal activity of Bt strains. In conclusion, both RAPD and PFGE are effective in the differentiation of Bt strains. The presence of cry2Aa1 and, especially, the expression level of cry1 genes are useful for the prediction of the insecticidal activities of Bt strains against P. xylostella.

  10. In vitro interaction of Metarhizium anisopliae Ma9236 and Beauveria bassiana Bb9205 with Heterorhabditis bacteriophora HNI0100 for the control of Plutella xylostella.

    Science.gov (United States)

    Correa-Cuadros, J P; Sáenz-Aponte, A; Rodríguez-Bocanegra, M X

    2016-01-01

    The diamondback moth (Plutella xylostella) is a major pest of broccoli crops in Colombia. To control P. xylostella, we evaluated the interaction of Beauveria bassiana Bb9205 and Metarhizium anisopliae Ma9236 with Heterorhabditis bacteriophora HNI0100 and its bacterial symbiont Photorhabdus luminescens HNI0100. We used antagonism and disk diffusion assays with fungal extracts to test the interaction between symbiotic bacterium and fungi. P. luminescens inhibited the growth of B. bassiana and M. anisopliae up to 40% by the secretion of secondary metabolites, whereas fungal extracts did not inhibit P. luminescens; this explains the in vivo interactions of these biological control agents. To test the interaction between fungi and nematodes, we first inoculated the fungi followed by the nematodes on different days (0, 2, 4, and 6). We identified the type of interaction using the formula by Nishimatsu and Jackson (J Econ Entomol 91:410-418, 1998) and established that on days 0, 2 and 4 there was an antagonistic interaction, while a synergistic interaction occurred on day 6. Therefore, the use of the interaction between H. bacteriophora HNI0100 with M. anisopliae Ma9236 and B. bassiana Bb9205 is an innovative alternative for the control of P. xylostella.

  11. Seleção e caracterização de estirpes de Bacillus thuringiensis efetivas no controle da traça-das-crucíferas Plutella xylostella Selection and characterization of Bacillus thuringiensis strains effective to control the diamondback moth Plutella xylostella

    Directory of Open Access Journals (Sweden)

    Patrícia Teles Medeiros

    2005-11-01

    Full Text Available O objetivo deste trabalho foi selecionar e caracterizar, no Banco de Germoplasma de Bacillus spp., da Empresa Brasileira de Pesquisa Agropecuária, as estirpes de Bacillus thuringiensis mais tóxicas à Plutella xylostella, por métodos morfológicos, bioquímicos e moleculares. Das 203 estirpes testadas, sete causaram 100% de mortalidade e foram semelhantes à estirpe padrão utilizada, B. thuringiensis subsp. kurstaki. Elas apresentaram proteínas de 130 kDa e 65 kDa, presença de genes cry1 e cry2 e cristais bipiramidais, cubóides e redondos. As estirpes selecionadas oferecem novas perspectivas de controle de P. xylostella.The aim of this work was to select and characterize the most toxic Bacillus thuringiensis strains, from the Germplasm Bank of Bacillus spp. of Empresa Brasileira de Pesquisa Agropecuária, against Plutella xylostella. Strains were characterized by morphological, biochemical and molecular methods. It was observed that seven out of the 203 strains tested showed high toxicity compared to the standard used B. thuringiensis subsp. kurstaki (HD-1, which showed 100% mortality. Selected strains showed features described for lepidoptera regarding the protein of 130 kDa and 65 kDa; profile and features were obtained through the PCR reactions, making possible to identify the presence of cry1 and cry2 genes. Moreover, the scanning electron microscopy showed the bipiramydal, cubed and round crystal forms. The selected strains offer new perspectives to control P. xylostella.

  12. Characterization of the mitochondrial genome of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) and phylogenetic analysis of advanced moths and butterflies.

    Science.gov (United States)

    Wei, Shu-Jun; Shi, Bao-Cai; Gong, Ya-Jun; Li, Qian; Chen, Xue-Xin

    2013-04-01

    Here we determined the mitochondrial genome sequence of a notorious pest, the diamondback moth Plutella xylostella (Lepidoptera: Yponomeutoidea: Plutellidae). The mitochondrial genome contains 37 typical animal mitochondrial genes and an A+T-rich region. The gene arrangement is identical to that of other ditrysian lepidopteran mitochondrial genomes, but different from the ancestral gene arrangement in the non-ditrysian Hepialidae of Lepidoptera. The start codon of the cox1 gene is CGA, which is dissimilar to its homologs in most other insects. In Lepidoptera, cox1 and cox2 have low nucleotide diversities, while the nad6, nad2, and nad3 genes are highly variable. Phylogenetic analyses uncovered the reciprocal monophyly of Ditrysia, Apoditrysia, Obtectomera, and Macrolepidoptera, and the placement of the Hesperiidae within Papilionoidea. Our analyses suggest that the complete mitochondrial genome sequences are a promising marker toward fully resolving the phylogenetic relationships within Lepidoptera.

  13. 苏云金杆菌干悬浮剂对小菜蛾的防治效果%Field Trails of Bacillus thuringiensis DF on Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    曹春霞; 王沫; 朱志刚; 黄大野; 龙同; 程贤亮

    2013-01-01

    干悬浮剂是一种新型、环保的农药剂型,采用不同处理浓度的苏云金杆菌(Bacillus thuringiensis)干悬浮剂防治小菜蛾(Plutella xylostella).结果表明,32 000 IU/mg苏云金杆菌干悬浮剂防治小菜蛾有较好的效果,450、600、750 g/hm2 3个处理浓度药后7d的防效分别为84.38%、91.04%、96.37%,可用于绿色及有机农业的生产.

  14. Aromatic glucosinolate biosynthesis pathway in Barbarea vulgaris and its response to Plutella xylostella infestation

    DEFF Research Database (Denmark)

    Liu, Tongjin; Zhang, Xiaohui; Yang, Haohui

    2016-01-01

    , showed only 77.50% identity in coding DNA sequences and 65.48% identity in deduced amino acid sequences. The homology to GS-OH in Arabidopsis, DBM induction of the transcript and a series of qPCR and glucosinolate analyses of G-type, P-type and F1 plants indicated that these genes control the production......The inducibility of the glucosinolate resistance mechanism is an energy-saving strategy for plants, but whether induction would still be triggered by glucosinolate-tolerant Plutella xylostella (diamondback moth, DBM) after a plant had evolved a new resistance mechanism (e.g., saponins in Barbara...... and their corresponding transcription factors were identified from an Illumina dataset of G- and P-type B. vulgaris. Many genes involved or potentially involved in glucosinolate biosynthesis were induced in both plant types. The expression patterns of six DBM induced genes were validated by quantitative PCR (qPCR), while...

  15. Quantification of γ-aminobutyric acid in the heads of houseflies (Musca domestica) and diamondback moths (Plutella xylostella (L.)), using capillary electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Shi, Xueyan; Liang, Pei; Song, Dunlun; Yang, Wenling; Gao, Xiwu

    2012-02-01

    A novel method was developed for quantifying the levels of γ-aminobutyric acid (GABA) in the heads of houseflies (Musca domestica) and diamondback moths (Plutella xylostella (L.)), using capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). The GABA in sample was derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-LIF analysis. In total, 32 mmol/L borate buffer, at pH 9.2 and containing 5.3 mmol/L β-cyclodextrin (β-CD) and 10.4 mmol/L sodium dodecyl sulfate (SDS), was determined to be the optimum CE background electrolyte (BGE) for GABA analysis. The detection limit of GABA was 0.016 μmol/L. The relative standard deviations (RSDs) of the migration time and peak area of GABA were 1.78 and 4.93%, respectively. The average recoveries of 0.97, 3.88, and 5.83 μmol/L of GABA, each added to the head sample of housefly, ranged from 88.9 to 110.5%. This method is simple and applicable to GABA assays of the heads of insects. With this newly developed CE-LIF method, the amounts of GABA in the heads of houseflies (M. domestica) and diamondback moths (P. xylostella (L.)) were measured. The results are relevant to the understandings of some insecticides and insecticide-resistance mechanisms in pests.

  16. CRISPR/Cas9 mediated knockout of the abdominal-A homeotic gene in the global pest, diamondback moth (Plutella xylostella).

    Science.gov (United States)

    Huang, Yuping; Chen, Yazhou; Zeng, Baosheng; Wang, Yajun; James, Anthony A; Gurr, Geoff M; Yang, Guang; Lin, Xijian; Huang, Yongping; You, Minsheng

    2016-08-01

    The diamondback moth, Plutella xylostella (L.), is a worldwide agricultural pest that has developed resistance to multiple classes of insecticides. Genetics-based approaches show promise as alternative pest management approaches but require functional studies to identify suitable gene targets. Here we use the CRISPR/Cas9 system to target a gene, abdominal-A, which has an important role in determining the identity and functionality of abdominal segments. We report that P. xylostella abdominal-A (Pxabd-A) has two structurally-similar splice isoforms (A and B) that differ only in the length of exon II, with 15 additional nucleotides in isoform A. Pxabd-A transcripts were detected in all developmental stages, and particularly in pupae and adults. CRISPR/Cas9-based mutagenesis of Pxabd-A exon I produced 91% chimeric mutants following injection of 448 eggs. Phenotypes with abnormal prolegs and malformed segments were visible in hatched larvae and unhatched embryos, and various defects were inherited by the next generation (G1). Genotyping of mutants demonstrated several mutations at the Pxabd-A genomic locus. The results indicate that a series of insertions and deletions were induced in the Pxabd-A locus, not only in G0 survivors but also in G1 individuals, and this provides a foundation for genome editing. Our study demonstrates the utility of the CRISPR/Cas9 system for targeting genes in an agricultural pest and therefore provides a foundation the development of novel pest management tools.

  17. The compatibility of a nucleopolyhedrosis virus control with resistance management for Bacillus thuringiensis: co-infection and cross-resistance studies with the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Raymond, B; Sayyed, A H; Wright, D J

    2006-10-01

    The use of genetically modified crops expressing Bacillus thuringiensis (Bt) toxins can lead to the reduction in application of broad-spectrum pesticides and an increased opportunity for supplementary biological control. Bt microbial sprays are also used by organic growers or as part of integrated pest management programs that rely on the use of natural enemies. In both applications the evolution of resistance to Bt toxins is a potential problem. Natural enemies (pathogens or insects) acting in combination with toxins can accelerate or decelerate the evolution of resistance to Bt. In the present study we investigated whether the use of a nucleopolyhedrovirus (AcMNPV) could potentially affect the evolution of resistance to the Bt toxin Cry1Ac in Plutella xylostella. At low toxin doses there was evidence for antagonistic interactions between AcMNPV and Cry1Ac resistant and susceptible insects. However, this antagonism was much stronger and more widespread for susceptible larvae; interactions were generally not distinguishable from additive for resistant larvae. Selection for resistance to Cry1Ac in two populations of P. xylostella with differing resistance mechanisms did not produce any correlated changes in resistance to AcMNPV. Stronger antagonistic interactions between Bt and AcMNPV on susceptible rather than resistant larvae can decrease the relative fitness between Bt-resistant and susceptible larvae. These interactions and the lack of cross-resistance between virus and toxin suggest that the use of NPV is compatible with resistance management to Bt products.

  18. Characterization and biotoxicity of Hypnea musciformis-synthesized silver nanoparticles as potential eco-friendly control tool against Aedes aegypti and Plutella xylostella.

    Science.gov (United States)

    Roni, Mathath; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Nicoletti, Marcello; Madhiyazhagan, Pari; Dinesh, Devakumar; Suresh, Udaiyan; Khater, Hanem F; Wei, Hui; Canale, Angelo; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Benelli, Giovanni

    2015-11-01

    Two of the most important challenges facing humanity in the 21st century comprise food production and disease control. Eco-friendly control tools against mosquito vectors and agricultural pests are urgently needed. Insecticidal products of marine origin have a huge potential to control these pests. In this research, we reported a single-step method to synthesize silver nanoparticles (AgNP) using the aqueous leaf extract of the seaweed Hypnea musciformis, a cheap, nontoxic and eco-friendly material, that worked as reducing and stabilizing agent during the biosynthesis. The formation of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometer. AgNP were characterized by FTIR, SEM, EDX and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and their mean size was 40-65nm. Low doses of H. musciformis aqueous extract and seaweed-synthesized AgNP showed larvicidal and pupicidal toxicity against the dengue vector Aedes aegypti and the cabbage pest Plutella xylostella. The LC50 value of AgNP ranged from 18.14 to 38.23ppm for 1st instar larvae (L1) and pupae of A. aegypti, and from 24.5 to 38.23ppm for L1 and pupae of P. xylostella. Both H. musciformis extract and AgNP strongly reduced longevity and fecundity of A. aegypti and P. xylostella adults. This study adds knowledge on the toxicity of seaweed borne insecticides and green-synthesized AgNP against arthropods of medical and agricultural importance, allowing us to propose the tested products as effective candidates to develop newer and cheap pest control tools. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Evaluation of the time-concentration-mortality responses of Plutella xylostella larvae to the interaction of Beauveria bassiana with a nereistoxin analogue insecticide.

    Science.gov (United States)

    Tian, Li; Feng, Ming-Guang

    2006-01-01

    Six bioassays were conducted to evaluate the interaction between Beauveria bassiana SG8702 and a nereistoxin analogue insecticide, diammonium S,S'-(2-dimethylaminotrimethylene)di(thiosulfate), which is highly compatible with the fungal biocontrol agent against diamondback moth Plutella xylostella (L.). Second-instar larvae were exposed to sprays of B. bassiana alone (assay 1) at concentrations of 21-38, 157-232 and 822-1133 conidia mm(-2) or together with the insecticide at the low application rates of 5, 10, 25, 50 and 100 microg AI ml(-1) (assays 2-6), and then maintained at 25 degrees C and 12:12 h light:dark photoperiod for daily monitoring of mortality for 8 days. Based on the modelling of the resultant time-concentration-mortality data sets, the fungal agent was highly virulent to P. xylostella with an LC50 decreasing from 269 conidia mm(-2) on day 4 to 107 on day 8. Lower lethal concentrations or shorter median lethal times resulted from fungal sprays including the tested chemical rates; the latter never caused higher mortalities than the fungal treatments alone. The fungal action over 3-7 days after spray was significantly enhanced by including in the fungal sprays the chemical at rates of > or =25 microg ml(-1) for 2.6- to 1756-fold reduction of LC50 values, > or =50 microg ml(-1) for 4- to 274-fold reduction of LC70 values and 100 microg ml(-1) for 9- to 33-fold reduction of LC90 values respectively. These rates were equivalent to 5-20% of the chemical rate labelled for field application. The fungal and chemical interaction outlined above highlights the feasibility of combined formulation or application of B. bassiana and the chemical insecticide for P. xylostella control.

  20. Capacidade de parasitismo de Trichogramma exiguum Pinto & Platner, 1978 (Hymenoptera: Trichogrammatidae em ovos de Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae em diferentes temperaturas Parasitism capacity of Trichogramma exiguum Pinto & Platner, 1978 (Hymenoptera: Trichogrammatidae on different temperatures on Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae eggs

    Directory of Open Access Journals (Sweden)

    Fabricio Fagundes Pereira

    2007-04-01

    Full Text Available Estudou-se a capacidade de parasitismo de Trichogramma exiguum Pinto & Platner, 1978 (Hymenoptera: Trichogrammatidae em ovos de Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae nas temperaturas de 18, 20, 22, 25, 28, 30 e 32°C, avaliando-se o número de ovos parasitados diariamente, a porcentagem acumulada de parasitismo, o número total de ovos parasitados por fêmea e a longevidade de fêmeas. O ritmo de parasitismo, durante as primeiras 24 horas, oscilou de 1,5 a 11,7 ovos parasitados por fêmeas de T. exiguum, nas temperaturas entre 18 e 32°C. O parasitismo acumulado de ovos de P. xylostella, nas temperaturas de 18, 20, 22, 25, 28, 30 e 32°C, atingiu 80%, respectivamente, aos 10, 7, 8, 5, 5, 4 e 5 dias, por T. exiguum. As maiores taxas de parasitismo obtidas por T. exiguum ocorreram nas faixas térmicas de 25, 30 e 32°C. A longevidade de fêmeas de T. exiguum, nas faixas térmicas compreendidas entre 18 e 32°C, variou de 4,2 a 7,4 dias.The parasitism capacity of Trichogramma exiguum Pinto & Platner, 1978 (Hymenoptera: Trichogrammatidae on eggs of Plutella xylostella (L., 1758 (Lepidoptera: Plutellidae was studied, under temperatures of 18, 20, 22, 25, 28, 30 and 32°C aiming at evaluating the number of days with parasitism, cumulated parasitism, total number of eggs parasited per female and their longevity. Parasitism during the first 24 hours ranged from 1.5 to 11.7 eggs of P. xylostella per T. exiguum female in the range of 18 to 32°C. Cumulated egg parasitism of P. xylostella by T. exiguum reached 80% after 10, 7, 8, 5, 5, 4 and 5 days at 18, 20, 22, 25, 28, 30 and 32°C. Higher parasitism rates were recorded at 25, 30 and 32°C while longevity of T. exiguum females varied from 4.2 to 7.4 days under temperatures of 18 to 32°C.

  1. Koolmot (Plutella xylostella)

    NARCIS (Netherlands)

    PPO Praktijkonderzoek Plant en Omgeving,

    2005-01-01

    In deze publicatie informatie over geleide bestrijding van rupsen van de koolmot in koolgewassen. Informatie over de levenscyclus van de koolmot en de schade die zij kunnen aanrichten in het gewas, de beheersstrategie met behulp van feromoonvallen en de bestrijding met behulp van middelen op basis v

  2. 茚虫威和高效氯氰菊酯对小菜蛾的亚致死效应%Sublethal effects of indoxacarb and beta-cypermethrin on Plutella xylostella (Lepidoptera: Plutellidae)

    Institute of Scientific and Technical Information of China (English)

    宋亮; 章金明; 吕要斌

    2013-01-01

    [目的]通过研究茚虫威和高效氯氰菊酯两种杀虫剂对小菜蛾Plutella xylostella (L.)的亚致死效应,进一步了解农药的杀虫机制,同时为合理使用农药、减少农药给环境和农业生产带来的一系列不良影响提供理论依据.[方法]浸叶法测定茚虫威和高效氯氰菊酯对小菜蛾2龄幼虫的毒力;选择茚虫威的3个实验浓度(TI-LC15,TI-LC30和TI-LC50)和高效氯氰菊酯的3个实验浓度(TB-LC15,TB-LC30和TB-LC50)分别处理小菜蛾2龄幼虫48 h,记录各虫态存活率和发育历期,3龄、4龄幼虫及蛹的重量,并记录单雌产卵量和成虫寿命;应用特征年龄-龄期及两性生命表方法,研究不同处理组小菜蛾后代的生长发育、存活率以及种群增长.[结果]TI-LC30,TI-LC50,TB-LC15,TB-LC30和TB-LC50处理组各虫态发育历期比对照组显著延长(P<0.05),3龄、4龄幼虫和蛹的重量以及单雌产卵量均显著低于对照组(P<0.05),但TI-LC15组小菜蛾3龄和4龄幼虫发育历期均显著低于对照组(P<0.05).TI-LC30,TI-LC50,TB-LC30和TB-LC50组小菜蛾后代的总产卵期显著短于相应对照组(P<0.05),产卵量也都显著降低(P <0.05);TI和TB实验组小菜蛾后代种群内禀增长率rm、周限增长率λ、净生殖率R0以及总生殖率GRR都比对照显著降低(P<0.05).[结论]低剂量的茚虫威和高效氯氰菊酯能显著抑制处理当代小菜蛾的生长发育和生殖,并对其下一代的生长发育及种群增长也有明显的抑制.%[Aim] In this study,the sublethal effects of indoxacarb and beta-cypermethrin on Plutella xylostella (L.) were investigated so as to further understand the mechanism of insecticides and provide a theoretical basis for proper application of pesticides and mitigating the damage to environment and negative effects on agriculture.[Methods] Leaf dipping method was used to test the acute toxicity of indoxacarb and beta-cypermethrin to the 2nd instar larvae of P.xylostella

  3. Effects of host plant on the oviposition preference of Plutella xylostella ( L.) and host- selection behavior of Cotesia plutellae (Kurdjmov).%寄主植物对小菜蛾产卵选择性及菜蛾绒茧蜂寄主选择行为的影响

    Institute of Scientific and Technical Information of China (English)

    江丽辉; 王栋; 刘树生

    2001-01-01

    测试了小菜蛾成虫对甘蓝和白菜的产卵选择性及菜蛾绒茧蜂对这两种蔬菜上寄主的寄生选择性。结果表明,当甘蓝和白菜同时存在时,小菜蛾在白菜上的产卵量约为甘蓝上的3倍。菜蛾绒茧蜂的寄主选择性试验表明,当两种蔬菜上寄主密度相同时,该蜂对白菜上小菜蛾幼虫的寄生数量接近甘蓝上的5倍。最后,对小菜蛾产卵选择性及菜蛾绒茧蜂的寄主选择行为与寄主植物的关系进行了讨论。%The ovipositional preference of the diamondback moth, Plutella xylostella (L.) between different Brassica vegetable plants and the host selection by Cotesia plutellae (Kurdjmov) between host larvae on different Brassica plants were studied. With the presence of both the Chinese cabbage, B. campestris L. ssp. pekinensis, the common cabbage, Brassica oleracea L. var. capitata, P. xylostella, moths laid three times as many eggs on the former as that on the latter plants. When C. plutellae wasps were provided with equal numbers of larvae of P. xylostella on both species of plants in one area, parasitism rate of hosts on B. campestris was almost five times that on B. oleracea. The possible effects of infochemicals from the Brassica plants on the oviposition preference of P. xylostella and on the host selection by C. plutellae were discussed.

  4. Temperature-dependent phenology of Plutella xylostella (Lepidoptera: Plutellidae): Simulation and visualization of current and future distributions along the Eastern Afromontane

    Science.gov (United States)

    Ngowi, Benignus V.; Tonnang, Henri E. Z.; Mwangi, Evans M.; Johansson, Tino; Ambale, Janet; Ndegwa, Paul N.

    2017-01-01

    There is a scarcity of laboratory and field-based results showing the movement of the diamondback moth (DBM) Plutella xylostella (L.) across a spatial scale. We studied the population growth of the diamondback moth (DBM) Plutella xylostella (L.) under six constant temperatures, to understand and predict population changes along altitudinal gradients and under climate change scenarios. Non-linear functions were fitted to continuously model DBM development, mortality, longevity and oviposition. We compiled the best-fitted functions for each life stage to yield a phenology model, which we stochastically simulated to estimate the life table parameters. Three temperature-dependent indices (establishment, generation and activity) were derived from a logistic population growth model and then coupled to collected current (2013) and downscaled temperature data from AFRICLIM (2055) for geospatial mapping. To measure and predict the impacts of temperature change on the pest’s biology, we mapped the indices along the altitudinal gradients of Mt. Kilimanjaro (Tanzania) and Taita Hills (Kenya) and assessed the differences between 2013 and 2055 climate scenarios. The optimal temperatures for development of DBM were 32.5, 33.5 and 33°C for eggs, larvae and pupae, respectively. Mortality rates increased due to extreme temperatures to 53.3, 70.0 and 52.4% for egg, larvae and pupae, respectively. The net reproduction rate reached a peak of 87.4 female offspring/female/generation at 20°C. Spatial simulations indicated that survival and establishment of DBM increased with a decrease in temperature, from low to high altitude. However, we observed a higher number of DBM generations at low altitude. The model predicted DBM population growth reduction in the low and medium altitudes by 2055. At higher altitude, it predicted an increase in the level of suitability for establishment with a decrease in the number of generations per year. If climate change occurs as per the selected

  5. Complex inheritance of larval adaptation in Plutella xylostella to a novel host plant

    NARCIS (Netherlands)

    K. Henniges-Janssen; A. Reineke; D.G. Heckel; A.T. Groot

    2011-01-01

    Studying the genetics of host shifts and range expansions in phytophagous insects contributes to our understanding of the evolution of host plant adaptation. We investigated the recent host range expansion to pea, in the pea-adapted strain (P-strain) of the crucifer-specialist diamondback moth, Plut

  6. Effects of selected insecticides on Diadegma semiclausum(Hymenoptera: Ichneumonidae) and Oomyzus sokolowskii (Hymenoptera: Eulophidae), parasitoids of Plutella xylostella (Lepidoptera: Plutellidae)

    Institute of Scientific and Technical Information of China (English)

    MUHAMMADHASEEB; HIROSHIAMANO; TONG-XIANLIU

    2005-01-01

    act Field doses of six selected insecticides were tested against the immature (pupae)and mature (adult) stages of Diadegma semiclausum (Hellén) and Oomyzus sokolowskii(Kurdjumov), parasitoids of the diamondback moth, Plutella xylostella (L.). Effects ofcontact toxicity (direct spraying) of the six insecticides on emergence of parasitoids were found negligible on both species except permethrin which caused 37.5% mortality. All adults of both parasitoid species died 24 hours after exposure to chlorfenapyr, emamectin benzoate and permethrin. In contrast, the three insect growth regulators (IGRs), chlorfluazuron,flufenoxuron and teflubenzuron, were found harmless to both species, and adult mortality of both parasitoid species was 0-16.7%. However, parasitism by the females of both parasitoid species was severely impaired when the females were offered the three IGR diluted solutions for 24 hours. Effects of oral toxicities of the IGRs on longevity of both parasitoids after 12 hours exposure were found to be significandy different between males and females. Compatibility of tested insecticides with D. semiclausum and O. sokolowskii and integration of compatible insecticides with these parasitoids in integrated pest management programs of crucifers are discussed.

  7. Mis-spliced transcripts of nicotinic acetylcholine receptor alpha6 are associated with field evolved spinosad resistance in Plutella xylostella (L..

    Directory of Open Access Journals (Sweden)

    Simon W Baxter

    2010-01-01

    Full Text Available The evolution of insecticide resistance is a global constraint to agricultural production. Spinosad is a new, low-environmental-risk insecticide that primarily targets nicotinic acetylcholine receptors (nAChR and is effective against a wide range of pest species. However, after only a few years of application, field evolved resistance emerged in the diamondback moth, Plutella xylostella, an important pest of brassica crops worldwide. Spinosad resistance in a Hawaiian population results from a single incompletely recessive and autosomal gene, and here we use AFLP linkage mapping to identify the chromosome controlling resistance in a backcross family. Recombinational mapping with more than 700 backcross progeny positioned a putative spinosad target, nAChR alpha 6 (Pxalpha6, at the resistance locus, PxSpinR. A mutation within the ninth intron splice junction of Pxalpha6 results in mis-splicing of transcripts, which produce a predicted protein truncated between the third and fourth transmembrane domains. Additional resistance-associated Pxalpha6 transcripts that excluded the mutation containing exon were detected, and these were also predicted to produce truncated proteins. Identification of the locus of resistance in this important crop pest will facilitate field monitoring of the spread of resistance and offer insights into the genetic basis of spinosad resistance in other species.

  8. GENETIC ANALYSIS OF CARTAP RESISTANCE IN DIAMONDBACK MOTH,PLUTELLA XYLOSTELLA (L.)%小菜蛾对杀螟丹抗性遗传的研究

    Institute of Scientific and Technical Information of China (English)

    程罗根; 李凤良; 陈之浩; 王荫长

    1999-01-01

    利用室内选育的抗杀螟丹小菜蛾Plutella xylostella(L.)品系和敏感品系研究了该品系的抗性遗传形式,结果表明,小菜蛾对杀螟丹的抗性形式为常染色体多基因遗传,并呈不完全显性.该品系对6种常用杀虫剂的抗性谱测定结果表明,对杀虫双有较严重的正交互抗性;对敌敌畏、杀扑磷有低度交互抗性;对溴氰菊酯、灭多威和叶蝉散等药剂无交互抗性.还发现该品系对杀螟丹的抗性与乙酰胆碱酯酶和羧酸酯酶活性无关.

  9. Resistance to the Bacillus thuringiensis bioinsecticide in a field population of Plutella xylostella is due to a change in a midgut membrane receptor.

    Science.gov (United States)

    Ferré, J; Real, M D; Van Rie, J; Jansens, S; Peferoen, M

    1991-06-15

    The biochemical mechanism for resistance to Bacillus thuringiensis crystal proteins was studied in a field population of diamondback moths (Plutella xylostella) with a reduced susceptibility to the bioinsecticidal spray. The toxicity and binding characteristics of three crystal proteins [CryIA(b), CryIB, and CryIC] were compared between the field population and a laboratory strain. The field population proved resistant (greater than 200-fold compared with the laboratory strain) to CryIA(b), one of the crystal proteins in the insecticidal formulation. Binding studies showed that the two strains differ in a membrane receptor that recognizes CryIA(b). This crystal protein did not bind to the brush-border membrane of the midgut epithelial cells of the field population, either because of strongly reduced binding affinity or because of the complete absence of the receptor molecule. Both strains proved fully susceptible to the CryIB and CryIC crystal proteins, which were not present in the B. thuringiensis formulation used in the field. Characteristics of CryIB and CryIC binding to brush-border membranes of midgut epithelial cells were virtually identical in the laboratory and the field population.

  10. Infection of Wolbachia in Plutella xylostella in Beijing area of China%Wolbachia在北京地区小菜蛾种群中的感染

    Institute of Scientific and Technical Information of China (English)

    宋月; 王哲; 刘宏岳; 沈佐锐

    2009-01-01

    Wolbachia是一类广泛分布于节肢动物体内,可以引起其寄主生殖行为改变的细胞内共生细菌.小菜蛾Plutella xylostella(L.)是常见的鳞翅目害虫,严重危害十字花科植物.通过对Wolbahcia的wsp基因的PCR扩增及克隆测序,明确Wolbachia在北京地区小菜蛾野生种群内及其个体体内的分布情况.研究发现,在北京地区小菜蛾的野生种群中,感染了一种Wolbahcia,将其命名为wXyl,并在GenBank中进行注册;在小菜蛾成虫的个体体内,其胸部,腹部及足内都有Wolbachia分布,而且所感染的Wolbachia完全相同.wXyl属于Wolbachia B组中的Pip亚组.研究首次发现在我国小菜蛾的野生种群内有Wolbachia感染的现象.

  11. Testing insecticidal activity of novel chemically synthesized siRNA against Plutella xylostella under laboratory and field conditions.

    Directory of Open Access Journals (Sweden)

    Liang Gong

    Full Text Available BACKGROUND: Over the last 60 years, synthetic chemical pesticides have served as a main tactic in the field of crop protection, but their availability is now declining as a result of the development of insect resistance. Therefore, alternative pest management agents are needed. However, the demonstration of RNAi gene silencing in insects and its successful usage in disrupting the expression of vital genes opened a door to the development of a variety of novel, environmentally sound approaches for insect pest management. METHODOLOGY/PRINCIPAL FINDINGS: Six small interfering RNAs (siRNAs were chemically synthesized and modified according to the cDNA sequence of P. xylostella acetylcholine esterase genes AChE1 and AChE2. All of them were formulated and used in insecticide activity screening against P. xylostella. Bioassay data suggested that Si-ace1_003 and Si-ace2_001 at a concentration of 3 µg cm(-2 displayed the best insecticidal activity with 73.7% and 89.0%, mortality, respectively. Additional bioassays were used to obtain the acute lethal concentrations of LC50 and LC90 for Si-ace2_001, which were 53.66 µg/ml and 759.71 µg/ml, respectively. Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2 were reduced by 5.7-fold compared to the control group. Consequently, AChE activity was also reduced by 1.7-fold. Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses. Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions. CONCLUSIONS: The most important finding of this study is the discovery that chemically synthesized and modified siRNA corresponding to P. xylostella AChE genes cause significant mortality of the insect both under laboratory and field conditions, which provides a novel strategy to control P

  12. Fluctuación poblacional y parasitismo de larvas de Copitarsia Decolora Guenée, Plutella Xylostella L. y Trichoplusia ni Hübner (Lepidoptera) en Brassica Oleracea L.

    OpenAIRE

    2007-01-01

    La fluctuación poblacional y los porcentajes de parasitismo se determinaron para larvas de Copitarsia decolora (Guenée), Plutella xylostella L. y Trichoplusia ni Hübner, asociadas con Brassica oleracea L. en tres variedades, col, coliflor y brócoli, durante abril de 2004 a abril de 2005, en Acatzingo, Puebla, México. Se realizaron muestreos al azar cada 14 días en 10 plantas por variedad; las larvas totales fueron contabilizadas, colectadas y mantenidas en una cámara de cría a 27º C ± 1º C y ...

  13. Effect of different plant extracts on prevention of oviposition in Plutella xylostella (L.) adults%10种植物提取物对小菜蛾产卵忌避作用研究初报

    Institute of Scientific and Technical Information of China (English)

    黎柳锋; 曾涛; 韦德卫; 陈海珊

    2011-01-01

    [目的]寻找新的小菜蛾生物防治方法,为植物源农药的研究和开发提供科学依据.[方法]以10种产于广西的楝科、番荔枝科、无患子科和报春花科植物提取物对小菜蛾成虫进行室内产卵忌避作用试验.[结果]以地黄连(Melia sinica)、香椿(叶)(Toona sinensis)、番荔枝(Annona squamosa)、四瓣米仔兰(A.terapetala)、灵香草(Lysimachia foenum-gmecum)等植物提取物处理后48 h对小菜蛾成虫的产卵忌避率分别为86.21%、94.69%、97.92%、98.91%和100.00%.[结论]地黄连、香椿(叶)、番荔枝、四瓣米仔兰、灵香草等5种植物对小菜蛾成虫有强烈的产卵忌避作用,在蔬菜害虫生态控制中均具有广阔的应用前景和开发潜力.%[Objective] The objective of the current study was to explore some biological control methods against Plutella xylostella (L.). [Method] The efficiency of extracts taken from 10 different plants (belonging to families meliaceae, annonaceae, sapindaceae and primulaceae) in preventing the oviposition in Plutella xylostella (L.) adults have been observed under laboratory conditions. [Result] The average oviposition deterrent rates of Plutella xylostella (L.). adults treated for 48 hour with extracts of Melia sinica, Toona sinensis (leaf) ,Annona squamosa, A. terapetala and Lysimachia foenum-graecum were 86.21, 94.69, 97.92, 98.91 and 100.00%, respectively. [Conclusion] Five plants, viz, Melia sinica, Toona sinensis (leaf) ,Annona squamosa, A. terapetala and Lysimachia foenum-graeeum were found to have the best control effects on oviposition of Plutella xylostella ( L ) adults, and they have broad application prospects and exploration potential as biological control agents against vegetable pests.

  14. Genetic Structure and Demographic History Reveal Migration of the Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae) from the Southern to Northern Regions of China

    Science.gov (United States)

    Wei, Shu-Jun; Shi, Bao-Cai; Gong, Ya-Jun; Jin, Gui-Hua; Chen, Xue-Xin; Meng, Xiang-Feng

    2013-01-01

    The diamondback moth Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) is one of the most destructive insect pests of cruciferous plants worldwide. Biological, ecological and genetic studies have indicated that this moth is migratory in many regions around the world. Although outbreaks of this pest occur annually in China and cause heavy damage, little is known concerning its migration. To better understand its migration pattern, we investigated the population genetic structure and demographic history of the diamondback moth by analyzing 27 geographical populations across China using four mitochondrial genes and nine microsatellite loci. The results showed that high haplotype diversity and low nucleotide diversity occurred in the diamondback moth populations, a finding that is typical for migratory species. No genetic differentiation among all populations and no correlation between genetic and geographical distance were found. However, pairwise analysis of the mitochondrial genes has indicated that populations from the southern region were more differentiated than those from the northern region. Gene flow analysis revealed that the effective number of migrants per generation into populations of the northern region is very high, whereas that into populations of the southern region is quite low. Neutrality testing, mismatch distribution and Bayesian Skyline Plot analyses based on mitochondrial genes all revealed that deviation from Hardy-Weinberg equilibrium and sudden expansion of the effective population size were present in populations from the northern region but not in those from the southern region. In conclusion, all our analyses strongly demonstrated that the diamondback moth migrates within China from the southern to northern regions with rare effective migration in the reverse direction. Our research provides a successful example of using population genetic approaches to resolve the seasonal migration of insects. PMID:23565158

  15. Identification of multiple small heat-shock protein genes in Plutella xylostella (L.) and their expression profiles in response to abiotic stresses.

    Science.gov (United States)

    Chen, Xi'en; Zhang, Yalin

    2015-01-01

    We identify and characterize 14 small heat-shock protein (sHSP) genes from the diamondback moth (DBM), Plutella xylostella (L.), a destructive pest. Phylogenetic analyses indicate that, except for sHSP18.8 and sHSP19.22, the other 12 DBM sHSPs belong to five known insect sHSP groups. Developmental expression analysis revealed that most sHSPs peaked in the pupal and adult stages. The transcripts of sHSPs display tissue specificity with two exhibiting constitutive expression in four tested tissues. Expression of sHSP18.8 in fourth instar larvae is not induced by the tested abiotic stressors, and unless sHSP21.8 is not sensitive to thermal stress, 12 sHSPs are significantly up-regulated. The messenger RNA (mRNA) levels of all sHSPs are reduced under oxidative stress. Food deprivation leads to significant down-regulation of three sHSPs. The majority of sHSPs show expression variation to various heavy metals, whereas mRNA abundances of sHSP22.1 and sHSP 28.9 are reduced by four heavy metals. The responses of sHSPs to indoxacarb and cantharidin are varied. Beta-cypermethrin and chlorfenapyr exposure results in an increase of 13 sHSP transcripts and a reduction of 12 sHSP transcripts, respectively. These results show that different sHSPs might play distinct roles in the development and regulation of physiological activities, as well as in response to various abiotic stresses of DBM.

  16. Resistance of Plutella xylostella (L.) to three new insecticides in field of different areas in Guangxi%广西不同地区小菜蛾田间种群对3种新型杀虫剂的抗性测定

    Institute of Scientific and Technical Information of China (English)

    梁育喆; 何宁祖; 谭辉华; 唐文伟

    2012-01-01

    [目的]测定广西6个蔬菜产区的小菜蛾田间种群幼虫对氯虫苯甲酰胺、氟虫双酰胺和氰氟虫腙等3种新型杀虫剂的敏感性,为3种杀虫剂的合理使用及各种群对3种药剂的抗性监测提供基础数据.[方法]采用浸叶法分别测定小菜蛾敏感品系和6个小菜蛾田间种群幼虫对氯虫苯甲酰胺、氟虫双酰胺、氰氟虫腙的敏感性,比较田间种群和敏感品系的LC50,计算小菜蛾田间种群的抗性倍数.[结果]小菜蛾荔浦种群对氯虫苯甲酰胺最敏感,其LC50为0.000735 mg/L,抗性倍数为1.32倍,田东种群的敏感性最低,其LC50为0.004230 mg/L,抗性倍数达7.61倍;对于氟虫双酰胺,柳江种群的敏感性相对较低,其LC50为0.366 mg/L,抗性倍数为2.27倍,南宁安吉种群最敏感,其LC50为0.168 mg/L,抗性倍数为1.04倍;对于氰氟虫腙,柳江种群的敏感性相对较低,其LC50为4.692 mg/L,抗性倍数为2.96倍,荔浦种群最敏感,其LC50为1.622mg/L,抗性倍数为1.02倍.[结论]小菜蛾田东种群对氯虫苯甲酰胺的抗性倍数为7.61倍,已达低水平抗性,应给予高度重视.其余地区的小菜蛾种群对3种杀虫剂的抗性倍数均低于5倍,仍处于敏感期,应加强不同药剂的轮换使用,以延缓小菜蛾抗性的形成与发展.%[Objective]The susceptibility of larval field population of Plutella xylostella in six vegetable areas in Guangxi against chlorantraniliprole, flubendiamide and metaflumizone were evaluated to provide a theoretical basis for application of pesticide in Plutella xylostella and their resistance monitoring to these pesticides. [Method]Comparative analysis on the LC50 value of the three pesticides between susceptible strains and field populations of Plutella xylostella, which employed the leaf dipping method (IRAC Method No. 7) to measure the toxicity of chlorantraniliprole, flubendiamide and metaflumizone against the larva of strain and the six field populations of Plutella

  17. 小菜蛾p38 MAPK基因的克隆与生物信息学分析%Cloning and Bioinformatic Analysis of p38 MAPK Gene from Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    胡霞; 谷希树; 刘晓琳; 白义川; 徐维红; 刘佰明; 许静杨

    2013-01-01

    小菜蛾(Plutella xylostellaL)是一种危害十字花科植物的世界性害虫,研究其基因功能为寻找新的小菜蛾防治方法具有重要意义.本研究克隆了小菜蛾p38 MAPK基因的开放阅读框(ORF),并根据其DNA序列推导出了蛋白一级结构,发现该基因编码一个含有349个氨基酸残基的蛋白.通过SMART网站分析发现该蛋白在第20 ~304位氨基酸残基区域存在着一个典型的丝氨酸/苏氨酸蛋白激酶结构域,说明它是一个潜在的丝氨酸/苏氨酸蛋白激酶.Blast比对发现Pxp38基因与家蚕Bmp38基因、酿酒酵母ScHOG1基因、人类Homo sapiens p38基因在蛋白一级结构上的相似性分别是91.7%、51.6%和78.6%,说明p38 MAPK基因在进化上具有较高的保守性.%Plutella xylostella L.is a major agricultural pest around the world,so the research on its gene function is important and meaningful to its biological control.In this study,the open reading frame (ORF) of Plutella xylostella p38 MAPK gene was cloned,and its protein primary structure was deduced according to the DNA sequence.It was found that the Pxp38 MAPK encoded a protein with 349 amino acid residues.By submitted to the SMART website,a classic Ser/Thr protein kinase domain was found between 20 ~ 304 amino acid residues,which indicated that Pxp38 MAPK gene was a putative Ser/Thr protein kinase.The similarity between Pxp38 and Bmp38,ScHog1,Homo sapiens p38 was 91.7%,51.6% and 78.6% respectively,which proved that p38 MAPK was highly conserved in evolution.

  18. 苏云金杆菌复配剂对小菜蛾和菜青虫的防治效果%Control Effect of Bacillus thuringiensis Compound on Plutella xylostella L. and Pieris rapae L.

    Institute of Scientific and Technical Information of China (English)

    杜传玉

    2007-01-01

    将苏云金杆菌(Bacillus thuringiensis,Bt)菌株20与生物杀虫剂Success混配制成复配剂,对2龄小菜蛾(Plutella xylostella L.)幼虫和菜青虫(Pierisrapae L.)的防治效果进行了田间药效试验.试验结果表明,该复配制剂可以有效防治菜青虫和抗性小菜蛾幼虫,其防治效果和杀虫速度均明显高于单独使用Bt菌株20和生物杀虫剂Success,表现出明显的增效作用.

  19. Isolation of High Toxin Bacillus thuringiensis against Plutella xylostella and Its Properties%一株对小菜蛾高毒力的苏云金杆菌的选育及研究

    Institute of Scientific and Technical Information of China (English)

    左雅慧; 徐宏英

    2002-01-01

    利用醋酸钠-抗生素法从土壤中分离出 1 株对小菜蛾(Plutella xylostella)高毒力的苏云金杆菌Bt-9905.该菌对小菜蛾 48 h的平均死亡率为 98.5 %.高于标准菌株HD-1( 81.2 %).同时,对该菌的形态、培养特征,生化特性和杀虫晶体蛋白的分子量的测定以及cry基因类型的鉴定进行了研究.

  20. N-Substituted 5-Chloro-6-phenylpyridazin-3(2H-ones: Synthesis, Insecticidal Activity Against Plutella xylostella (L. and SAR Study

    Directory of Open Access Journals (Sweden)

    Song Yang

    2012-08-01

    Full Text Available A series of N-substituted 5-chloro-6-phenylpyridazin-3(2H-one derivatives were synthesized based on our previous work; all compounds were characterized by spectral data and tested for in vitro insecticidal activity against Plutella xylostella. The results showed that the synthesized pyridazin-3(2H-one compounds possessed good insecticidal activities, especially the compounds 4b, 4d, and 4h which showed > 90% activity at 100 mg/L. The structure-activity relationships (SAR for these compounds were also discussed.

  1. Comparison of Susceptibility of Plutella xylostella to Nine Insecticides in Different Areas of Jiangxi Province%江西不同地区小菜蛾对9种杀虫剂的敏感性比较

    Institute of Scientific and Technical Information of China (English)

    陈洁琼; 黄水金; 邱高辉; 管德泳; 秦文婧; 陈琼; 秦厚国

    2014-01-01

    2013年采取浸叶法测定了江西省5个地区田间小菜蛾对9种杀虫剂的敏感性。结果表明:小菜蛾5个地理种群对BT、溴虫腈和丁醚脲表现为敏感至低水平抗性;对啶虫隆、氯虫苯甲酰胺和茚虫威均表现为中等及其以下水平抗性;对阿维菌素和高效氯氰菊酯已产生了高水平的抗性。除了吉水种群对多杀菌素表现出高抗外,其余4个种群均表现出中等或中等以下水平抗性。%The susceptibility of field populations of Plutella xylostella from five areas of Jiangxi province to nine insecticides was tested by using leaf-dipping method in 2013.It was found that 5 field populations of Plutella xylostella showed sensitive or low re-sistance to BT, Chlorfenapyr and Diafenthiuron , moderate or middle-low resistance to Chlorfluazuron , Chlorantraniliprole and In-doxacarb, and high resistance to Abamectin and beta -Cypermethrin.Among the tested five populations , the field population in Jishui revealed a high resistance to Spinosad , while the others showed a moderate or middle -low resistance to this insecticide .

  2. Study on the Effect of Allylisothiocyanate Formulations on Three Lepidopterous Insect Larvae, the Diamond Back Moth, Plutella xylostella (L., the Small Cabbage White Butterfly, Pieris rapae (L. and Tobacco Cut Worm, Spodoptera litura Fabr

    Directory of Open Access Journals (Sweden)

    E. M. Eltayeb

    2010-01-01

    Full Text Available Problem statement: The toxicity of seven of Allylisothiocyanate (AITC formulations, AITC pure and in mixture with cypermethrin and chlorpyrifos, was evaluated using spray application and fumigation method against the diamondback moth, Plutella xylostella (L., the small cabbage white butterfly, Pieris rapae (L. and the tobacco cut worm, Spodoptera litura Fabr. Approach: Response varied according to insect species, specific formulation and AITC application rates. Results: Fumigant toxicity of the oil based on 9 h exposure was evaluated against the three insect larvae, the diamond back moth, P. xylostella larvae were more susceptible followed by tobacco cut worm, S. litura and cabbage white, P. rapae larvae. To P. xylostella larvae, LC50 value was 1.5 µL L-1 air, S. litura larvae (LC50, 1.8 µL L-1 air and P. rapae larvae (LC50, 2.0 µL L-1 air. These three insect larvae were killed after 9 h exposure to a dose of 4.3 µL L-1 air of the oil, showed no significance difference with that of phosphine (40 µg L-1 air a recommended dose. On the other hand, on the spray application bioassays, mortality data counted 72h after treatment, the P. rapae larvae were most susceptible to AITC formulations followed by S. litura larvae and P. xylostella larvae. LC50 values, to P. xylostella larvae, HJ(A and HJ(B were the most potent toxicant (33 mg L -1 and (46 mg L-1 respectively, while the least toxic was HJ(C (556 mg L-1. To S. litura larvae, HJ(B and HJ(A were the most efficient (10 mg L-1 and (22 mg L-1 respectively, while HJ(D (LC50, 385 mg L-1 was found to be the least toxic. The both of HJ (B and HJ (C had similar insecticidal activity (LC50, 8 mg L-1 to Pieris rapae larvae followed by HD (B (LC50, 22 mg L-1 and HD (A (LC50, 82 mg L-1. Conclusion/Recommendations: It was concluded that the AITC oil showed promise findings and may be a good alternative to old fumigant “phosphine”. The others were found efficient on the spray application bioassays but the

  3. Effect of low dose spinetoram on detoxification enzymes inPlutella xylostella%低剂量乙基多杀菌素对小菜蛾解毒酶的影响

    Institute of Scientific and Technical Information of China (English)

    田雪莲; 尹显慧; 龙友华; 李明; 蔡滔; 李荣玉; 朱流红

    2016-01-01

    为探讨低剂量乙基多杀菌素对小菜蛾Plutella xylostella (L.)解毒酶的影响,采用叶片浸渍法,测定了乙基多杀菌素和多杀菌素对小菜蛾敏感种群的毒力,并比较了低剂量(LC25和LC50)处理6、12、24、48和72 h时小菜蛾体内羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GST)和多功能氧化酶系(MFOs)活性的变化动态。结果表明:乙基多杀菌素对小菜蛾的杀虫活性优于多杀菌素,处理48 h后其 LC25和 LC50浓度分别为0.018和0.048 mg/L,经此低剂量浓度处理后,小菜蛾 CarE活性波动较大,6~24 h,处理组 CarE活性高于对照组,且均呈先升后降趋势,24~72 h,处理组 CarE活性均低于对照组,并且具有一定的时间效应;对 GST具有明显的诱导作用,GST活性均高于对照组;对 MFOs具有明显的抑制作用,除在48 h时相差不大外,其他时间 MFOs活性均显著低于对照组。结果表明,GST可能参与了乙基多杀菌素在小菜蛾体内的代谢。%To clarify the effects of low dose spinetoram on the activitiy of detoxifying enzymes in Plutella xylostella (L.), the toxicities of spinetoram and spinosad to susceptible population ofP. xylostella were assayed using leaf dipping method. And the changing dynamics of detoxifying enzymes of carboxylesterase, glutathioneS-transferase and mixed-functional oxidase were measured after exposure to LC25 and LC50 doses of spinetoram at 6, 12, 24, 48 and 72 h, respectively. The results showed that the spinetoram had higher toxicity toP. xylostella than that of spinosad. The 48 h LC25 and LC50 of spinetoram were 0.018 and 0.048 mg/L, respectively. After treatment with low concentrations spinetoram, a large fluctuation of the CarE was observed. CarE activity in the treatment strain were higher than those in the untreated control strain after treatment 6-24 h, and showed tendency of first increasing and then decreasing. Whereas, from 24 h to 72 h, CarE activity was lower

  4. Effects of Barbarea vulgaris Rosette Plants on Oviposition Preference of Plutella xylostella with Different Experiences%欧洲山芥对不同经历的小菜蛾产卵选择行为的影响

    Institute of Scientific and Technical Information of China (English)

    吕建华; 刘树生

    2011-01-01

    The effects of rosette plants of Barbarea vulgaris on oviposition preference of the diamondback moth (DBM) Plutella xylostella (L.) female moths with different experiences were studied in laboratory.The results showed that different experiences of DBM during both larva and early adult stage and adult stage indeed enhanced oviposition preference of DBM to the host plants fed on or experienced its leaf volatiles by DBM.However, the increased preference to the plants was still not strong enough to significantly alter extremely strong attractiveness of Barbarea vulgaris to ovipositing P.xylostella.%在实验室内研究了莲座期欧洲山芥对不同经历的小菜蛾雌成虫产卵选择行为的影响.结果表明,小菜蛾在幼虫期及成虫前期的不同经历、成虫期的不同经历均能够显著增强其对所经历寄主植物的产卵偏好性,但仍然不能改变欧洲山芥对小菜蛾具有的极强的产卵引诱力.

  5. Optimization of Artificial Rearing Methods for Plutella xylostella L. (Plutellidae) and Its Susceptibility to Five Types of Insecticides%小菜蛾的人工饲养方法优化和对几种农药敏感性测定

    Institute of Scientific and Technical Information of China (English)

    王静; 朱九生

    2012-01-01

    [目的]优化小菜蛾(Plutella xylostella L.)的人工饲养方法,筛选防治小菜蛾的有效药剂。[方法]在温度25±1℃、相对湿度60%~75%、光照周期L:D=(14:10)h条件下,用吹塑纸收集小菜蛾卵,用小油菜(Brassica chinensis)苗饲养幼虫;同时采用浸叶法,测定小菜蛾对5种供试药剂的敏感性。[结果]用小油菜苗饲养的小菜蛾发育状况良好,其蛹重为5.4mg/头,羽化率为94.O%,每雌产卵量为135.1粒。200g/L氯虫苯甲酰胺SC、20%氟虫双酰胺WG、150g,L茚虫威EC、200g/L虫酰肼Sc和1.8%阿维菌素EC对小菜蛾3龄幼虫的LC50值分别为0.152、0.223、1.151、93.340和0.128mg/L。[结论]该饲养方法操作简单,实用性强,适合于小菜蛾的批量繁殖;阿维菌素、氯虫苯甲酰胺和氟虫双酰胺对小菜蛾有较高杀虫活性,3种农药可交替轮换使用防治小菜蛾。%[Objective] The research aimed to optimize laboratory artificial rearing methods for Plutella xylostella L. and to select out effective insecticides against this pest species. [Method] Brassica chinensis seedlings were cultivated in the laboratory at (25±1)℃, 60-75% RH, and a photoperiod of 14:10 (L:D) h. The green blow molding papers were used to collect eggs, and Brassica oleracea seedlings were cultivated to breed Plutella xylostella L. until the insects were ready for use. Mean-while, the susceptibility of 3rd instar larvae of Plutella xylostella L. to five types of insecticides was tested by leaf-dipping method. [Result] Plutella xylostella L. larvae were found well-grown and uniform in developmental stages with average pupa weight of 5.4 mg, pupa emergence percentage of 94.0 % and egg number of 135.1 per female. The LCso values of 3rd instar Plutella xylostella L. larvae against 200 g/L chlorantraniliprole SC, 20% flubendiamide WG, 150 g/L indoxacarb EC, 200 g/L tebufenozide SC and 1.8% abamectin

  6. The Entomopathogenic Fungi Isaria fumosorosea Plays a Vital Role in Suppressing the Immune System of Plutella xylostella: RNA-Seq and DGE Analysis of Immunity-Related Genes

    Directory of Open Access Journals (Sweden)

    Jin Xu

    2017-07-01

    Full Text Available Most, if not all, entomopathogenic fungi have been used as alternative control agents to decrease the insect resistance and harmful effects of the insecticides on the environment. Among them, Isaria fumosorosea has also shown great potential to control different insect pests. In the present study, we explored the immune response of P. xylostella to the infection of I. fumosorosea at different time points by using RNA-Sequencing and differential gene expression technology at the genomic level. To gain insight into the host-pathogen interaction at the genomic level, five libraries of P. xylostella larvae at 12, 18, 24, and 36 h post-infection and a control were constructed. In total, 161 immunity-related genes were identified and grouped into four categories; immune recognition families, toll and Imd pathway, melanization, and antimicrobial peptides (AMPs. The results of differentially expressed immunity-related genes depicted that 15, 13, 53, and 14 up-regulated and 38, 51, 56, and 49 were down-regulated in P. xylostella at 12, 18, 24, and 36 h post-treatment, respectively. RNA-Seq results of immunity-related genes revealed that the expression of AMPs was reduced after treatment with I. fumosorosea. To validate RNA-Seq results by RT-qPCR, 22 immunity-related genes were randomly selected. In conclusion, our results demonstrate that I. fumosorosea has the potential to suppress the immune response of P. xylostella and can become a potential biopesticide for controlling P. xylostella.

  7. Effect of silencing midgut cadherin gene on susceptibility of Plutella xylostella larvae to Cry1Ac toxin%沉默cadherin基因对小菜蛾敏感性的影响

    Institute of Scientific and Technical Information of China (English)

    杨中侠; 杨柳; 谭济才; 吴青君; 王少丽; 徐宝云; 张友军

    2013-01-01

    钙粘蛋白(cadherin)是许多鳞翅目昆虫中苏云金芽孢杆菌(Bt)毒素的受体.利用RNAi技术对小菜蛾中肠cadherin基因进行沉默处理,明确了cadherin基因沉默对小菜蛾对Cry1 Ac毒素敏感性的影响.结果表明,注射目标dsRNA后的第1天至第5天,Cry1 Ac敏感及抗性小菜蛾品系cadherin的基因表达量均显著减少,尤以第2天的减少量最为明显;Cry1 Ac毒力测定结果表明,沉默cadherin基因能在一定程度上提高幼虫的成活率,即可使小菜蛾对Cry1 Ac毒素的敏感性降低.研究初步表明,cadherin基因的功能与小菜蛾对Cry1Ac毒素的抗性有关.%Cadherin was confirmed to be the receptor of Bacillus thuringiensis (Bt) insecticidal protein in several Lepidoptera insects.Cadherin gene in Plutella xylostella was silenced by RNAi technique and effect of cadherin gene silencing on susceptibility of P.xylostella larvae to Cry1Ac toxin was investigated.The results showed that the expression level of cadherin gene reduced from the first day to the fifth day after the dsRNA corresponding to cadherin segment was injected,and the most significant reduction was observed sharply at the second day.The susceptibility of resistant and susceptible strain of P.xylostella larvae to Cry1Ac toxin decreased after cadherin gene being silenced.The results suggested that cadherin gene was related to resistance of P.xylostella to Cry1Ac toxin.

  8. Study on Binding Pattern of Antennal Binding Protein PxylABP in Plutella xylostella%小菜蛾触角结合蛋白 PxylABP 结合模式的研究

    Institute of Scientific and Technical Information of China (English)

    邓培渊; 袁伟; 李玉华; 王林青; 李长看

    2016-01-01

    Antennal binding proteins are soluble acidic proteins in insect antenna.It is an important way to clarify ABP physiological function by analysising the binding pattern.The PxylABP gene of Plutella xylostella was cloned using reverse transcription PCR and expressed in Escherichia coli.The specificity of PxylABP binding with 29 compounds was tested through fluorescence competitive binding assay,and the molecular docking of PxylABP with compounds were carried out using AutoDock 4.2.The results showed that PxylABP protein had binding ability to Allylisothiocyanate,Hexane,Hexanal,Indole,2-hexanone and β-Lonone,with the dissociation constants of 0.91 , 1 .81 ,1 .1 7,2.71 ,2.74 and 1 4.95 μmol /L,respcetively;The molecular docking results showed that one hydrogen bond generated between Tyr1 00 and Allyl-isothiocyanate.These data suggested that PxylABP might be involved in the physiological process that discriminate the cruciferous vegetables and herbivore-induced plant volatiles in Plutel-la xylostella.%为了研究触角结合蛋白(Antennal binding proteins,ABPs)的生理功能,利用 RT-PCR 方法克隆了小菜蛾 Pxy-lABP 基因,并在大肠杆菌中表达,纯化的重组蛋白通过荧光竞争结合试验测定其与29种化合物的结合特性,并运用AutoDock 4.2进行 PxylABP 蛋白和化合物的分子对接。结果表明,PxylABP 与异硫氰酸丙烯酯、己醛、己烷、2-己酮、吲哚和β-紫罗兰酮结合,解离常数分别为0.91,1.81,1.17,2.71,2.74,14.95μmol /L;分子对接显示,Tyr100与异硫氰酸丙烯酯形成1个氢键。说明 PxylABP 参与了小菜蛾识别十字花科蔬菜和虫害诱导的植物挥发物的生理过程。

  9. Studies on Application of the Extract from Azadirachta indica A.Juss for Control of Plutella xylostella L.Larvae%印楝素对小菜蛾幼虫的防治效果研究

    Institute of Scientific and Technical Information of China (English)

    黄春萍; 李琪; 程晋伟; 陈洁; 宗浩

    2012-01-01

    为了研究无公害生物农药对小菜蛾的防治效果,采用固-液连续萃取法提取印楝(Azadirachta india A.Juss)种仁的活性物质,减压浓缩后得到粗提物,得率13.8%;应用高效液相色谱测得浸膏中楝素的含量为17 mg/g.室内毒力测定结果表明该提取物对小菜蛾(Plutella xylostella L.)幼虫具有较强的毒杀作用;用不同稀释倍数的种仁甲醇粗提物对小菜蛾幼虫进行了拒食作用的测定,试虫的拒食率分别达到37.5%、47.6%和61.9%.结果表明印楝提取物对小菜蛾幼虫具有较好的防治效果.%The toxieity of the extract from neem tree (Azadiachta Mica A.Juss) to the diamondback moth (Plutella xylostella L. ) was evaluated in laboratory to study the application of the pollution-free biological pesticides. The extracting rate of the methanol extract from neem kernel was 13.8 % ,and the azadiraehtin obtained was 17 mg/g by HPLC. In a laboratory study, the methanol extract was effective against the diamondback moth larvae. The antifeedant effect of the diamondback moth larvae on the extract from neem tree was determined. The antifeedant rate of the different concentrations against the diamondback moth larvae were 37.5 %, 46.7 % and 61.9 %, respectively, 24 h after treated by feeding method. The results showed that the extract from the neem had strong control of the diamondback moth.

  10. Uji Aktivitas Beberapa Konsentrasi Ekstrak Daun Dan Buah Mengkudu (Morinda citrifolia L.) Terhadap Ulat Tritip Plutella Xylostella L. (Lepidoptera : Plutellidae) Di Laboratorium

    OpenAIRE

    Ginting, Maria

    2012-01-01

    This research is aim to to know activity from leaf extract and mengkudu fruit (M L citrifolia.) to tritip caterpillar ( P. xylostella L.). This Research is executed on Laboratory Pest Plant Faculty Of Agriculture University North Sumatra with height + 25 metre highland and was done on April - May 2005. This research use Factorial Complete Random Device with 2 Factor that is DB (Extract Leaf and Mengkudu fruit) and K ( Concentration). Consist with 6 treatment and 4 replicates. That is DK...

  11. Preliminary research on oviposition preference of Plutella xylostella to Pugionium cornutum%小菜蛾成虫对沙芥的产卵嗜好性的初步研究

    Institute of Scientific and Technical Information of China (English)

    徐世才; 贺达汉; 刘军和; 毛玉涛

    2006-01-01

    通过室内试验,比较了小菜蛾 Plutella xylostella L.对沙生十字花科蔬菜沙芥叶(Puggioniumcornutum L.)、小白菜、油菜和甘蓝叶的产卵选择性.结果表明,产卵选择性顺序为:沙芥≥小白菜>油菜>甘蓝,在沙芥叶上的产卵率是甘蓝叶上的9倍多;补充营养使小菜蛾成虫的产卵量平均提高2.5倍,产卵次数增加2倍,在有沙芥叶条件下,当日羽化的小菜蛾便可交尾产卵;在无沙芥叶条件下,小菜蛾成虫的产卵前期平均延迟1 d左右.

  12. Bioactivity of 6 Insecticides to Different Developmental Stages ofPlutella xylostella (L.)%6种杀虫剂对小菜蛾不同虫态室内活性研究

    Institute of Scientific and Technical Information of China (English)

    洪珊珊; 贾变桃; 李琴; 张琰锋

    2014-01-01

    Bioactivities of chlorfenapyr, lufenuron, chlorantraniliprole, indoxacarb, abamectin and spinosad to eggs, larvae, pupae and adults ofPlutella xylostella were studied by egg-dipping method, leaf-dipping method, immersion method and residual film method in the laboratory. The results showed that the six insecticides had excellent effects on larvaeof P. xylostella. Chlorfenapyr and spinosad had quick bioactivities after 24 h treatment, and the corrected mortalities were above 90%. The corrected mortalities of chlorfenapyr, chlorantraniliprole, abamectin and spinosadreached 100% after 72 h treatment, the corrected mortality of indoxacarb were 98.2%. All of the six insecticides had certain ovicidal effects, ovicidal activity of lufenuron was high, abamectin and spinosad had low ovicidal activities, but could kill neonate larvae and decrease survival rates of larvae. The survival rates of 2nd instar larvae were below 10% after eggs treated with field doses of all six insecticides. Among six insecticides, chlorfenapyr and indoxacarb showed higher toxic to pupae and adults ofP. xylostella, the other four insecticides had a little or no toxic to pupae and adults ofP. xylostella.%为了解不同杀虫剂对小菜蛾的杀虫活性,采用浸卵法、浸叶法、浸渍法和药膜法分别测定了6种杀虫剂(虫螨腈、虱螨脲、氯虫苯甲酰胺、茚虫威、阿维菌素和多杀霉素)对小菜蛾卵、幼虫、蛹和成虫4种不同虫态的室内活性。结果表明:田间推荐剂量下,6种杀虫剂对小菜蛾幼虫具有很高的杀虫活性,虫螨腈和多杀霉素具有速效性,药后24 h校正死亡率在90%以上。药后72 h,虫螨腈、氯虫苯甲酰胺、阿维菌素和多杀霉素这4种药剂校正死亡率达100%。此外,6种杀虫剂均具有一定的杀卵作用,杀卵活性最强的是虱螨脲,多杀霉素和阿维菌素的杀卵作用较差。尽管有些杀虫剂杀卵作用稍差,但这些药剂可以杀死初孵幼虫

  13. The symptoms and histopathological changes of Plutella xylostella larvae infected with Isaria fumosorosea%小菜蛾感染玫烟色棒束孢后的病征及组织病理变化

    Institute of Scientific and Technical Information of China (English)

    雷妍圆; 吕利华; 何余容; 韦秉兴

    2011-01-01

    为了明确玫烟色棒束孢对小菜蛾的致病作用,分别以1x105孢子/mL和1X108孢子/mL浓度的玫烟色棒束孢菌株EBCL03011孢子悬浮液感染小菜蛾幼虫,观察了感病幼虫体表和体内器官组织的病变情况.结果显示,感病虫体颜色由局部浅褐色逐渐变为大面积深褐色,病虫出现缩短、强直等外部形态的变化.组织切片观察显示,接种后4h,附着于体壁的分生孢子开始萌发入侵;16h后,小菜蛾内表皮被分解,菌丝段进入血腔.与此同时,被幼虫取食进入消化道的分生孢子也增殖产生菌丝段,以菌丝段突破肠壁细胞,向附近的脂肪体入侵;随着玫烟色棒束孢继续在虫体内增殖,24h后各组织器官遭到不同程度破坏;48h后,感病幼虫死亡,虫尸体内的菌丝突破体表,在虫体外形成菌丝层.表明玫烟色棒束孢入侵小菜蛾有两条途径,第1条为体表途径,第2条为消化道途径.%In order to clarify the pathogenicity of Isariafumosorosea (Paecilomyces fumosoroseus) (Hypocreales: Cordycipitaceae) to Plutella xylostella ( Lepidoptera: Plutellidae), The tissues and organs of P.xylostella larvae infected with an indigenous strain EBCL 03011 suspension of I.fumosorosea at two concentrations of 1 × 105 conidia/mL and 1 × 108 conidia/mL were investigated. The results showed that infected larvae cuticle gradually became dark brown, the whole body of the insect thickened and reduced in size. Paraffin sections of infected larvae organs observed under light microscope indicated that the conidia of I. fumosorosea attached with the integument of P. xylostella larvae penetrated through the cuticle by germ tubes after 4 h postinoculation. After 16 h, the endocuticle and gut wall cells were disintegrated, the germ tubes passed through the epithelial layers and gut cavity into the hemocoel, then invaded the muscle tissues and fat body nearby the area of penetration. After 24 h, most tissues and organs of infected larvae had

  14. 小菜蛾田间种群对杀虫剂的抗药性测定%Determination of Pesticide Resistance of Plutella xylostella Field Population

    Institute of Scientific and Technical Information of China (English)

    程英; 李凤良; 金剑雪; 李忠英

    2012-01-01

    In order to explore the pesticide resistance of P. xylostella field population, leaf-dip method and drop method were used to determine their resistance to 13 kinds of pesticides in Guiyang, Anshun and Zunyi, including spinosad, chlorfenapyr, thuricide and so on. The results showed that in the three areas P. xylostella field population had very high sensitivity to spinosad, chlorfenapyr and thuricide. But low sensitivity to cartap and dimehypo, and they had severe resistance to abamectin, emamectin benzoate and pyrethroid insecticides.%为弄清小菜蛾田间种群对杀虫剂的抗药性,采用浸叶和点滴方法,就贵阳、安顺和遵义3个地区的小菜蛾田间种群对多杀霉素、虫螨腈和苏云金杆菌等13种杀虫剂的抗药性进行了测定.结果表明:3个地区小菜蛾田间种群对多杀霉素、虫螨腈、苏云金杆菌和氟虫腈的敏感性很高,对杀螟丹和杀虫双的敏感性较差,对阿维菌素、甲维盐和拟除虫菊酯类杀虫剂产生了严重的抗药性.

  15. Ginkgolic Acids from Ginkgo Exocarp and Their Toxicity to the Diamondback Moth, Plutella xylostella%银杏外种皮中银杏酚酸对小菜蛾幼虫的拒食及毒杀作用

    Institute of Scientific and Technical Information of China (English)

    郭春霞; 傅大煦; 周铜水; 李博; 董慧琴

    2004-01-01

    小菜蛾(Plutella xylostella L.)是一种全球性的重要害虫,其抗药性引起国际学术界的广泛关注,而开发高效、低毒、低残留、无污染的生物农药成为了国内外农药开发的主流.报道了从废弃的银杏(Ginkgo bilobaL.) 外种皮中分离到的银杏酚酸对小菜蛾的拒食和毒杀作用.实验采用皂化和酯化反应及柱层析方法从银杏外种皮中分离获得银杏酚酸,并对1~3龄小菜蛾幼虫进行生物测定.生测结果表明银杏酚酸对小菜蛾有较好的拒食和毒杀作用.当处理的质量浓度为6.25 mg/L时3龄幼虫的非选择性拒食率在24,48 h后分别达到77.8%,94.7%以上.处理时间达到48 h时,1~2龄幼虫的LC50为1.31 mg/L,3龄幼虫的LC50为6.07 mg/L.这表明了银杏外种皮有很好的开发前景,将为今后新型植物农药的开发和银杏废弃物的综合利用提供依据.

  16. Selective Toxicities of 12 Insecticides to Plutella Xylostella and Diadegma Semiclausum%12种杀虫剂对小菜蛾及半闭弯尾姬蜂的选择毒力

    Institute of Scientific and Technical Information of China (English)

    洪珊珊; 贾变桃; 张雨超; 曹永伟

    2015-01-01

    The toxicity of 12 insecticides to Plutella xylostella and its parasitoidDiadegma semiclausum was determined with leaf‐dip method and vial residual film method ,respectively ,and the selective toxicity between P. xylostella andD.semiclausum was compared. The results showed that the order of toxicity of 12 insecticides to the larvae of dia‐mondback moth was emamectin benzoate > sophocarpidine > pinetoram > abamectin > spinosad > chlorantraniliprole >lufenuron > ndoxacarb > chlorfenapyr > diafenthiuron > chlorpyrifos > beta‐cypermethrin ;the order of toxicity of 12 in‐secticides to the adults of D.semiclausum was beta‐cypermethrin > emamectin benzoate > sophocarpidine > spinetoram >chlorpyrifos > abamectin > spinosad > chlorfenapyr > indoxacarb > chlorantraniliprole > diafenthiuron > lufenu‐ron. Lufenuron showed highest positive selectivity to D.semiclausum and P. xylostella with the selective toxicity ratio (STR) > 1 141.6 ,chlorantraniliprole showed higher positive selectivity with STR 169.2. The four insecticides (sopho‐carpidine ,abamectin ,emamectin benzoate ,spinetoram ) showed moderately positive selectivity ,and their STR was 19.8 ~ 57.0.Diafenthiuron ,oxacarb ,spinosad and chlorfenapyr showed low positive selectivity ,and their STR was 1.9 ~ 6.6.Chlorpyrifos and beta‐cypermethrin showed negative selective toxicity to D.semiclausum and P. xylostella , their STR were lowest with 9.0 × 10 - 3 and 0.9 × 10 - 3 ,respectively. The data presented in this paper provided guideline for reasonable use of insecticides and coordinating chemical and biological control of P. xylostella.%采用浸叶法和试管药膜法分别测定了12种杀虫剂对小菜蛾3龄幼虫及其天敌半闭弯尾姬蜂的毒力,比较不同药剂在害虫和天敌之间的选择毒力。结果表明,杀虫剂对小菜蛾幼虫毒力大小顺序为甲维盐>苦参碱>乙基多杀菌素>阿维菌素>氯虫苯甲酰胺>多杀菌素>虱螨脲>茚虫威>溴

  17. Field Experiment of 0.3% Azadiracht in EW Controlling Plutella Xylostella of Cruciferous Vegeta-bles%0.3%印楝素水剂防治十字花科蔬菜小菜蛾田间试验

    Institute of Scientific and Technical Information of China (English)

    高洋; 李江岩; 季明刚

    2015-01-01

    In order to evaluate the effects of different dosages on the prevention activity of Plutella xylostel⁃la,0.3% Azadirachtin EW were used to protect Cabbage from Plutella xylostella in fields, and comparison of activity with EC was also made. The results showed that under the dosage of 7.2~10.8g(a.i.)/hm2, the prevention activity could reach over 90% on each treatment after 10 days over 0.3% Azadirachtin EW, and no significant difference of prevention activity was observed between EC and EW under same dosage of Azadirachtin. In the application of 0.3% Azadirachtin EW to protect Cabbage from Plutella xylostella in fields,the dosage of Azadirachtin were suggested to be 9~10.8g(a.i.)/hm2.%为了明确0.3%印楝素水剂不同用药量对防治小菜蛾的防治效果,开展了该药剂防治田间甘蓝小菜蛾效果试验。结果表明,在7.2~10.8g(a.i.)/hm2用量下,各药剂处理10d平均防治效果均高于90%;在相同用药量情况下,水剂剂型的防效与乳油剂型无显著差异。建议在防治小菜蛾时采用0.3%印楝素水剂的使用剂量为9.0~10.8g(a.i.)/hm2。

  18. Physiological defense responses of Plutella xylostella(Lepidoptera: Plutellidae)larvae infected by entomopathogenic fungus Isaria fumosorosea%小菜蛾血淋巴对玫烟色棒束孢入侵的生理防御反应

    Institute of Scientific and Technical Information of China (English)

    雷妍圆; 何余容; 吕利华

    2011-01-01

    To explore the defense responses of PluteUa xylostella ( Lepidoptera: Plutellidae) hemolymph against the infection of different strains of entoraopathogenic fungus Isaria fumosorosea (syn. Paecilomyces fumosoroseus) ( Hypocreales: Cordycipitaceae) , cellular immune responses of the infected 4th instar larvae was investigated with optics microscope and Giemsa stain. The results indicated that the invasion of P. Xylosetlla by /. Fumosorosea resulted in changes in the characteristics of host hemolymph, including the initial increase of the total numbers of hemocytes, and the change of the proportion of differential hemoeytes in association with fungal infection processes. During 8 - 45 h post inoculation, the peak response reached to 6 250/mm3 at 24 h after invasion by the highly pathogenic strain PFCF-001. The highest total hemocyte counts (3 000/mm3 ) were observed at 36 h when P. Xylostella larvae were inoculated with the least pathogenic strain PFCF-D58, which was 12 h later than the treatment of strain PFCF-001. The major defense hemocytes were plasmatocytes and granulocytes. Different types of cellular immune responses were observed at the early stage of infection including adhesion, phagocytosis, hemocytic aggregation, encapsulation and nodule formation. However, the defense responses of the P. Xyolstella against the highly pathogenic strain of /. Fumosorosea just inhibited the pathogen temporarily but could not clear it completely.%为了探讨小菜蛾Plutella xylostella血淋巴对玫烟色棒束孢Isaria fumosorosea的防御机制,利用吉姆萨染色法在光镜下观察了小菜蛾4龄幼虫血细胞感染不同致病力玫烟色棒束孢后的免疫反应.结果表明:玫烟色棒束孢的入侵可导致小菜蛾血细胞数量发生改变,表现为入侵初期血细胞总数增加,不同类型血细胞比例改变等.体表接种后8-45 h,高致病力菌株PFCF-001处理的幼虫血细胞总数在24h出现最高值6 250个/mm3,

  19. Population dynamics and insecticide resistance of Plutella xylostella in Inner Mongolia%内蒙古小菜蛾种群数量动态及抗药性监测

    Institute of Scientific and Technical Information of China (English)

    周晓榕; 常静; 庞保平; 吴青君; 张友军

    2013-01-01

    2009-2011年对内蒙古呼和浩特市郊区十字花科蔬菜和武川县油菜上小菜蛾Plutella xylostella(L.)种群消长动态进行了调查,并比较了呼和浩特地区小菜蛾对11种杀虫剂的抗药性.结果表明,在呼和浩特郊区,小菜蛾成虫于4月上旬开始出现,一年中有4个发生高峰,分别为4月下旬或5月上旬、6月中旬、8月下旬和10月上旬;小菜蛾幼虫在春甘蓝和秋白菜整个生长期间均有发生,大约有4个发生高峰,分别为6月上中旬、6月下旬或7月上旬、9月上旬和10月上旬.在武川县,小菜蛾成虫于4月末或5月初开始发生,春夏季数量高于秋季,共有2个发生高峰,2009年为5月下旬和6月中旬,2010年为6月上旬和8月上中旬;小菜蛾幼虫在6月下旬开始出现,在油菜整个生长期间,小菜蛾幼虫约有3个数量高峰,分别为7月初、7月末和8月下旬,秋季数量高于春夏季.在供试的11种杀虫剂中,溴虫腈对小菜蛾幼虫的毒力最高,LC50为0.22 mg·L-1;其次为多杀菌素、氯虫苯甲酰胺、氟虫腈和BT,LC50分别为0.82 ~0.83、1.09、1.36和3.41 mg·L-1;再次为茚虫威和阿维菌素,LC50分别为15.74 mg·L-1和6.03~23.47 mg·L-1;然后为丁醚尿、虫酰肼和啶虫隆,LC50分别为51.30、52.66和61.91 mg·L-1;最低为高效氯氰菊酯,LC50为462.66~673.26 mg·L-1.抗药性测定表明,呼和浩特地区小菜蛾幼虫未对溴虫腈、虫酰肼、氯虫苯甲酰胺和丁醚尿产生抗性,对多杀菌素和氟虫腈为低抗性,对茚虫威和BT为中抗性,对高效氯氰菊酯、啶虫隆和阿维菌素为极高抗性.%The population dynamics and insecticide resistance of the diamondback moth, Plutetla xylostella ( L.) , were investigated on cruciferous vegetables in a Hohhot suburb, and on rapeseed in Wuchuan County, Inner Mongolia from 2009 to 2011. In the suburb of Hohhot city, adult moths began to occur in early April and had four peaks of abundance during the year: late

  20. Parasitism-induced effects on host growth and metabolic efficiency in Plutella xylostella larvae parasitized by Cotesia vestalis or Diadegma semiclausum

    Institute of Scientific and Technical Information of China (English)

    Fang Huang; Ting-Ting Cao; Min Shi; Ya-Feng Chen; Xue-xin Chen

    2008-01-01

    The nutritional physiology of the diamondback moth,Plutellaxylostella,larvae was examined after parasitization by the solitary endoparasitoids Cotesia vestalis or Diadegrna semiclausum.Examinations were performed in two phases,one was examined at the time point of 24 h post-parasitization,and the other was done at the end of the 4th instar larvae of host.Rates of growth,food consumption,assimilation,excretion,and respiration were calculated as well as approximate digestibility and the rate ratios ECI (percent efficiency of conversion of ingested food to body substance),and ECD (percent efficiency of conversion of digested food to body substance).Parasitization by C.vestalis resulted in significant decrease in the rates of growth,feeding,excretion,assimilation,and respiration,but the final dry rate of respiration at the end of last larval stadium was elevated.The ECI and ECD were also reduced as the result of parasitization,but digestibility was increased.All these parameters in the larvae parasitized by D.semiclausum at 24 h post-parasitization were also significantly changed compared to the control;however,these differences were quantitatively,but not qualitatively before pupation,similar to those resulted from parasitization by C.vestalis.In spite of the similarities of the parasitism-induced effects caused by these endoparasitoids,the final metabolic rate,that is,the rate of intake of nutrients required to compensate for metabolism,was much lower in the larvae parasitized by C.vestalis than that of the larvae parasitized by D.semiclausum.All of the results discussed here will contribute toward explaining the different ways these two wasps regulate the parasitoid-host relationship.

  1. A peptidoglycan recognition protein (PxPGRP-SA) regulating the expression of antimicrobial peptides in Plutella xylostella (Lepidoptera: Plutellidae)%一个调控抗菌肽表达的小菜蛾肽聚糖识别蛋白(PxPGRP-SA)

    Institute of Scientific and Technical Information of China (English)

    郑志华; 许小霞; 余静; 高延富; 张玉清; 欧阳莉娜; 金丰良

    2016-01-01

    [目的]肽聚糖识别蛋白(peptidoglycan recognition proteins,PGRPs)是昆虫免疫系统中一类重要的模式识别蛋白.本研究旨在阐明经苏云金芽孢杆菌Bacillus thuringiensis侵染后,小菜蛾Plutella xylostella PGRP-SA基因(命名为PxPGRP-SA)在体内的表达模式和对抗菌肽基因的表达调控.[方法]本研究利用实时荧光定量PCR (qRT-PCR)技术分析B.thuringiensis侵染小菜蛾幼虫后PxPGRP-SA的转录模式,通过RNAi技术结合抗血清封闭实验检测PxPGRP-SA对小菜蛾抗茵肽基因的表达调控作用.[结果]qRT-PCR检测表明,小菜蛾4龄幼虫在注射具有活性的B.thuringiensis 6 h后,PxPGRP-SA在脂肪体和血细胞中表达量迅速上升,其中脂肪体中的表达量在注射24 h后达到高峰,而在血细胞中的表达量在18 h后达到高峰.RNAi沉默小菜蛾4龄幼虫PxPGRP-SA的转录后,可显著降低小菜蛾脂肪体中cecropin,moricin-2,lysozyme和defensin4个抗茵肽基因及Dorsal和Sp(a)tzle基因的mRNA转录水平;注射anti-PxPGRP-SA封闭小菜蛾体内PxPGRP-SA的活性后,也可降低小菜蛾脂肪体中4个抗菌肽基因的mRNA转录水平;PxPGRP-SA转录沉默后,同时导致添食B.thuringiensis的小菜蛾幼虫的存活率明显降低.[结论]PxPGRP-SA参与了小菜蛾体内抗茵肽cecropin,moricin-2,lysozyme和defensin基因的表达调控,并在免疫防御B.thuringiensis的侵染过程中起了重要的作用.%[Aim] Peptidoglycan recognition proteins (PGRPs) are one kind of important pattern recognition proteins in insect immune system.In this study,we aim to investigate the expression patterns of PGRP-SA from Plutella xylostella (designated as PxPGRP-SA) and its involvement in the regulation of the expression of antimicrobial peptide genes in P.xylostella after infection by Bacillus thuringiensis.[Methods] The transcription pattern of PxPGRP-SA in P.xylostella larvae infected by B.thuringiensis was analyzed by quantitative real-time reverse transcription

  2. 十一种农药对小菜蛾的毒力及其天敌草间小黑蛛的安全性%The toxicities of 11 kinds of insecticides to the diamondback moth, Plutella xylostella and its natural enemy Erigonidium graminicolum

    Institute of Scientific and Technical Information of China (English)

    章金明; 吕要斌; 林文彩; 黄芳; 贝亚维; 张蓬军; 陈诚

    2011-01-01

    通过室内试验,评价了11种农药对3龄小菜蛾Plutella xylostella(L.)幼虫的毒性及其天敌草间小黑蛛的安全性.研究结果表明,苏云金杆菌、氟虫腈、溴虫腈、多杀菌素和丁醚脲对小菜蛾3龄幼虫的杀虫效果最好,致死率达100%;啶虫隆和巴丹效果次之,致死率分别为90.0%和87.5%.对于草间小黑蛛Erigonidiumgraminicolum(Sunderall)幼蛛,丁醚脲、苏云金杆菌、虫酰肼、啶虫隆的初始毒性和持续毒性均较低,接触药膜48 h后致死率都低于30%;而对于草间小黑蛛成蛛,除阿维菌素、高效氯氰菊酯和巴丹外,其余8种农药毒性较低,死亡率低于20%;综合11种农药对小菜蛾和蜘蛛的毒性,苏云金杆菌、丁醚脲、多杀菌素的选择毒性最好,优先推荐在蜘蛛等天敌多的季节使用.%The toxicities of 11 kinds of insecticides to the 3rd instar larvae of the diamondback moth ( DBM ), Plutella xylostella (L.), and its natural enemy Erigonidium graminicolum (Sundervall), were assayed under laboratory conditions. The results demonstrate that Bt, fipronil, chlorfenapyr, spinosad and diafenthiuron could kill 100% of DBM larvae, followed by chlorfluazuron and cartap which killed 90. 0% and 87. 5% , respectively. Diafenthiuron, Bt,tebufenozide and chlorfluazuron both showed lower initial and persistent toxicities against E. graminicolum larvae;mortality was < 30% after being subjected to a toxic film of these pesticides for 48 hours. In contrast, the other 8 kinds of insecticides, except for avermectin, alpha-cypermethrin and cartap, caused < 20% mortality of E. graminicolum adults. Based on these results, Bt, diafenthiuron, spinosad are the best pesticides to control P. xylostella, especially when E. graminicolum is abundant.

  3. Determination of Plutella xylostella(L.)Resistance to Nine Insecticides in Central China%华中地区小菜蛾对9种杀虫剂的抗药性测定

    Institute of Scientific and Technical Information of China (English)

    夏耀民; 鲁艳辉; 朱勋; 申君; 游红; 李建洪

    2013-01-01

    采用室内浸叶法,测定了华中地区5个蔬菜产区(河南洛阳白马寺镇、湖南岳阳广兴洲镇、湖北武穴梅川镇、湖北宜昌当阳市、湖北云梦隔蒲镇)田间小菜蛾种群对2%阿维菌素乳油(EC)、16000 IU·mg-1 Bt工程菌WG-001可湿性粉剂(WP)、20%高效氯氰菊酯EC、5%氯虫苯甲酰胺EC、2.5%多杀菌素悬浮剂(SC)、10%溴虫腈EC、5%氟啶脲EC、20%丁醚脲EC、5%茚虫威EC等9种常用杀虫剂的抗药性。结果表明:5个小菜蛾种群对阿维菌素(抗药性倍数为44.5~92.0倍)、Bt(抗药性倍数为66.5~202.1倍)、高效氯氰菊酯(抗药性倍数为76.2~146.4倍)已产生了高水平至极高水平抗性,对氟啶脲(抗药性倍数为32.5~82.5倍)的抗药性达到中等至高水平抗性,对多杀菌素(抗药性倍数为6.5~19.4倍)、氯虫苯甲酰胺(抗药性倍数为3.1~23.1倍)、溴虫腈(抗药性倍数为2.6~22.3倍)和茚虫威(抗药性倍数为7.1~26.3倍)表现为中等及以下水平抗性,对丁醚脲(抗药性倍数为2.3~7.7倍)表现为敏感至低水平抗性。因此,华中地区的小菜蛾防治应注重氯虫苯甲酰胺、溴虫腈、丁醚脲与多杀菌素、茚虫威、氟啶脲交替、轮换使用,以便延缓抗药性的产生与发展,取得更好的防效。%Five field populations of diamondback moth,Plutella xylostella,including Luoyang in Henan Province,Yueyang in Hunan Province,and Wuxue,Yunmeng and Yichang in Hubei Province, were collected from the central China.P. xylostella populations had resistance to 9 insecticides as 2%abamectin EC,16 000 IU·mg-1 Bt WG-001 WP,20%beta-cypermethrin EC,5%chlorantraniliprole EC,2.5% spinosad SC,10% chlorfenapyr EC,5% chlorfluazuron EC,20% diafenthiuron EC,5%indoxacarb EC.The bioassay results indicated that 5 populations exhibited high to extreme high level of resistance to abamectin,Bt,beta-cypermethrin,with the resistance ratio 44

  4. 4 Parasitism of Plutella xylostella.cdr

    African Journals Online (AJOL)

    Administrator

    biological control agents and the development ... Department of Animal Biology and Conservation Science, University of Ghana, Legon,. Accra ... and implementation of biological control- ..... metabolites from the entomopathogenic nematode.

  5. Screening of optimum proportion and field effect of mixtures of Bt engineering strain WG-001 and chemical insecticides against Plutella xylostella%Bt工程菌WG-001与化学杀虫剂复配最佳配方筛选及田间防效研究

    Institute of Scientific and Technical Information of China (English)

    张聪冲; 邱浩; 覃春华; 游红; 李建洪

    2011-01-01

    为了延缓小菜蛾Plutella xylostella(L.)抗药性的产生和发展,筛选Bt工程菌WG-001与化学杀虫剂的最佳复配配方,本研究采用浸叶法分别测定了Bt工程菌WG-001与茚虫威、丁醚脲和巴丹复配对小菜蛾的增效作用.结果表明,当Bt工程菌WG-001与茚虫威以有效成分之比为100.10:0.72复配时,增效作用最强,共毒系数为178.05.而Bt工程菌WG-001分别与丁醚脲和巴丹复配表现相加或拮抗作用.田间试验结果表明,Bt工程菌WG-001与茚虫威以100.10:0.72的有效成分之比进行复配后,药后7 d,500倍液对小菜蛾的平均防效为84.88%,显著优于Bt工程菌WG-001和茚虫威单用的平均防效.%The relative effectiveness of mixtures of the Bt strain WG-001 with the pesticides indoxacarb, diafenthiuron and cartap for controlling the diamondback moth ( DBM ) Plutella xylostella ( L. ) was determined using the leaf-dipping method. The results indicate that a 100.10:0.72 mixture of Bt strain WG-001 and indoxacarb was the most synergetic with a co-toxicity coefficient (CTC) of 178.05. Mixtures of Bt strain WG-001 with diafenthiuron or cartap had an additive or antagonistic action, respectively. Results of a field trial showed that the average control effect of a 500 times dilution of the Bt strain WG-001 and indoxacarb mixture was 84.88% 7 days after treatment, significantly higher than using either Bt WG-001 or indoxacarb separately ( P <0.05 ).

  6. 山西十字花科小菜蛾种群消长动态及几种杀虫剂的触杀毒力比较%Population dynamics of Plutella xylostella in cruciferae plants and contact toxicity of insecticides to it in Shanxi area

    Institute of Scientific and Technical Information of China (English)

    张贵云; 张丽萍; 刘珍; 魏明峰; 范巧兰; 吴青君; 张友军

    2011-01-01

    The population dynamics of the diamondback moth, Plutella xylostella ( L. ) feeding on 3 cruciferous plants in the Shanxi area were investigated in 2009 and 2010. Over the same period, the contact toxicity of insecticides introduced to control P. xylostella was evaluated. Differences in the population dynamics of P. xylostella between 2009 and 2010 were due to different weather conditions in these years. In 2009, P. xylostella first appeared on April 1 st , two clear peaks of abundance occurred in late April and late May, respectively and there was no clear peak of abundance in the fall. The 1st generation eggs were laid on May 8th and the 1st generation pupae were found on May 18th. The total quantity of eggs and larvae peaked on May 13th and September 1st, and on May 23th and September 16th, respectively. In 2010, P.xylostella first appeared on March 15th, and three different peaks of abundance occurred in early April, late May to earlyJune and mid - October. 1 st generation eggs were laid on May 26th and 1 st generation pupae were found on June 5th. The total quantity of eggs and larvae peaked on May 15th and September 25a, and June 15th and October 10th, respectively.Numbers of P. xylostella on vegetables were higher than on weeds in 2009 and 2010. Contact toxieities of the 11 insecticides were tested using the leaf dipping bioassay method. The results indicate that Spinosad was the most toxic with an LD50 value of 0.01 μg/ larva. Chlorfluazuron, Diafenthiuron and Tebufenozide were more toxic than the other pesticides tested, having LDso values of 0. 34, 0. 28 and 0. 10 μg/larva, respectively. Cypermethrin and Cartap were the least toxic, with LDso values of 91.53 and 84.36 μg/larva, respectively.%2009--2010连续两年,对山西省十字花科甘蓝、萝卜和杂草上的小菜蛾Plutella xylostella(L.)种群消长动态进行了调查,并对11种杀虫剂的触杀毒力进行了比较分析.结果表明,受特殊气候条件影响,山西省2009与2010年

  7. 蝉拟青霉侵染小菜蛾幼虫SSH文库的构建及免疫相关基因分析%Construction of Suppression Subtractive Hybridization Library of Plutella xylostella Immunized by Paecilomyces cicadae and Analysis of Immune-related Genes

    Institute of Scientific and Technical Information of China (English)

    党向利; 陈官菊; 厉晓腊; 刘又高; 金轶伟; 易辉玉; 吕要斌; 柴一秋

    2012-01-01

    为探讨小菜蛾Plutella xylostella对病原真菌入侵的免疫防御机制,利用抑制消减杂交技术构建蝉拟青霉Paecilomyces cicadae侵染的小菜蛾幼虫的抑制性差减文库,并对文库进行鉴定。ESTs序列聚类分析共获得412个独立基因。通过同源比对,28.24%ESTs为未知功能基因,71.76%ESTs与已知功能基因序列相似,包括免疫相关、金属离子结合和加工、核酸和蛋白代谢及加工、细胞信号、细胞结构、形状和流动、能量代谢、胁迫和解毒以及其它基因。鉴定出39个可能参与小菜蛾免疫蝉拟青霉侵染的免疫基因,包括:识别分子、蛋白酶及蛋白酶抑制剂、效应因子及其它免疫基因。qRT-PCR结果表明肽聚糖识别蛋白、器官芽生长因子、葛佬素、溶菌酶、酚氧化酶原激活蛋白酶3以及转铁蛋白基因均可诱导表达。免疫相关基因在不同微生物诱导下的表达模式存在不同。结果表明当病原真菌蝉拟青霉侵染寄主小菜蛾后,小菜蛾体内发生了一系列的复杂反应,小菜蛾抵御病原真菌侵染是一个多途径共同作用的复杂过程。该研究为进一步研究小菜蛾抵御病原真菌入侵的分子机制提供基础信息。%In the present study,the innate immune response of Plutella xylostella against Paecilomyces cicadae challenges was surveyed using a constructed suppression subtractive hybridization library.A total of 825 P.xylostella ESTs were obtained.They were assembled to 412 unigenes(including 107 contigs and 305 unique sequences).By BLASTN,28.24% of the P.xylostella ESTs had no hit or hitted on unknown gene.71.76% ESTs were subjected to annotated and categorized by their putative functions,including immunity-related genes,metal ion binding and processing,nucleic acid and protein metabolism and process,cell signaling,cell structure,shape and mobility,energy metabolism,stress and detoxification and other genes.GeneOntology revealed that 39

  8. Bacillus thuringiensis resistance in Plutella - too many trees?

    Science.gov (United States)

    Crickmore, Neil

    2016-06-01

    Plutella xylostella was the first insect for which resistance to Bacillus thuringiensis was reported in the field, yet despite many studies on the nature of this resistance phenotype its genetic and molecular basis remains elusive. Many different factors have been proposed as contributing to resistance, although in many cases it has not been possible to establish a causal link. Indeed, there are so many studies published that it has become very difficult to 'see the wood for the trees'. This article will attempt to clarify our current understanding of Bt resistance in P. xylostella and consider the criteria that are used when validating a particular model.

  9. Influence of three volatiles from tropical rank grasses on behavior of Plutella xylostella%3种热带杂草挥发油干扰小菜蛾行为的研究

    Institute of Scientific and Technical Information of China (English)

    覃伟权; 张茂新; 凌冰; 彭正强

    2004-01-01

    利用嗅觉反应研究了3种热带杂草挥发油对小菜蛾Plutella xylostella行为的影响. 结果表明,3种热带杂草挥发油对小菜蛾Plutella xylostella成虫有好的驱避作用,且随挥发油量的增加驱避作用加强,白花蒿Artemisia argyi和假蒟Piper betle 2种挥发油比飞机草Eupatorium odoratum挥发油对成虫的驱避作用更明显. 在产卵驱避和拒食作用试验中,3种热带杂草挥发油对小菜蛾表现出一定的产卵驱避作用和拒食作用,且随着施用浓度的增加产卵驱避和拒食作用加强,随着时间的延长产卵驱避作用和拒食作用减弱. 3种挥发油的产卵驱避效果和拒食活性大小分别为:假蒟挥发油>飞机草挥发油>白花蒿挥发油.

  10. 温度、湿度和覆土对小菜蛾羽化的影响%Effects of temperature, soil humidity and soil cover on Plutella xylostella (Lepidoptera: Plutellidae) pupae emergence

    Institute of Scientific and Technical Information of China (English)

    周福才; 胡其靖; 江解增; 顾爱祥; 任佳; 杨爱民; 邵久之

    2012-01-01

    XPlutella xylostella is one of the main pests that affect vegetable commodity output. Current treatment by chemical pesticide spray has been considered the effective control of P. xylostella. This treatment has also developed the insecticide resistance, increased pesticide residue risks and threatened pollution-free vegetable production. In the present study, the effects of abio-chemical conditions such as temperature, soil moisture, water-logging and soil cover on P. xylostella pupae eclosion were investigated. The study aimed to elucidate agro-measure control effects, especially those of paddy/dryland rotation and soil plowing, on P. xylostella. The results showed that the rate of pupa emergence exceeded 73% at 26-30 °C, which declined to 46.67% at 34 °C. When treated at 4 °C and then grown at room temperature, the rate of pupae emergence dropped significantly. The longer the 4 °C pretreatment, the lower was the rate of pupae emergence. However, the emergency rate recovered to normal levels after long time of growth at room temperature. When soil moisture was 10% and 20%, the emergence rate was respectively 12.5% and 6.2% of that under normal moisture condition. No pupa emergence was observed within 6 d at soil moisture of 30%. When treated with water-logging for 12 h and 24 h and then returned to surface soil, the rate of emergence of P. xylostella pupae dropped respectively by 25.0% and 50.0% and emergency was delayed too. No pupa emergence was observed under extended treatment time of 36 h. Soil covering also had noticeable effects on P. xylostella pupa emergence. The emergence of pupae was delayed by 2 d when covered at 1 cm depth soil. Pupa did not successfully emerge when soil cover was 1.5 cm deep. The above results suggested that timely irrigation, paddy/dryland rotation and soil plowing were critical control factors of P. xylostella pupae in vegetable fields.%小菜蛾是蔬菜的重要害虫,其非化学控制技术对蔬菜的安全生产非常重

  11. 绿僵菌侵染小菜蛾幼虫过程的透射电镜观察%Observation of infection process of Metarhizium anisopliae on Plutella xylostella larvae with transmission electron microscopy

    Institute of Scientific and Technical Information of China (English)

    王音; 雷仲仁; 张青文; 问锦曾

    2006-01-01

    利用透射电镜观察了绿僵菌Metarhizium anisopliae对小菜蛾Plutella xylostella幼虫的侵染过程.结果表明:接种后22 h最早观察到绿僵菌穿透到寄主表皮层中,在穿透表皮过程中伴随着机械力和酶的活动.菌体进入寄主血腔后,以菌丝出芽生殖、菌丝分隔及菌丝段分隔3种方式大量增殖,主要形成颗粒状的菌丝段在寄主体腔内扩散,也形成少量的丝状菌丝.

  12. The Stability of Resistance and the Strategies for Management of Insecticide Resistance in Plutella xylostella(L.)%小菜蛾抗性稳定性及抗性治理对策研究

    Institute of Scientific and Technical Information of China (English)

    吴刚; 尤民生; 赵士熙

    2001-01-01

    试验表明,福州地区田间小菜蛾已对有机磷、氨基甲酸酯及拟除虫菊酯产生高抗性。脱离选择压力3代后,小菜蛾的抗性水平迅速下降。Bt预处理可提高抗性和敏感小菜蛾幼虫对有机磷的敏感性,尤其对抗性小菜蛾增效极显著,对敏感小菜蛾AChE的Ki值则影响不大。据此提出在抗性治理中,应轮用或换用不同毒理机制的杀虫剂,且其间隔至少为2~3代。%High resistances to organophosphates(OPs), carbamates and pyrethroids were found in the field strain of diamondback moth(DBM),P. xylostella(L.),in Fuzhou,Fujian Province. The resistance quickly decreased after DBM were released from selection pressure for only 3 generations,and significant synergism to OPs in R strain was found after 24 h pretreatment with Bt. The activities of AchE were strongly depressed by Bt pretreatment in R Strain. The higher values of Ki were detected in R Strain with Bt pretreatment, but no significant changes in S strain. The results showed that the resistance management of insecticides with different toxicity mechanism, in volving alternating and mixing insecticide, should be adopted in IPM strategies.

  13. The influences of site-directed mutation on the toxicity of Bacillus thuringiensis CrylBa3 polypeptide against Plutella xylostella%苏云金芽胞杆菌Cry1Ba3蛋白定点突变对杀小菜蛾活性的影响

    Institute of Scientific and Technical Information of China (English)

    林承喜; 束长龙; 翟元娜; 林毅; 宋福平; 张杰

    2011-01-01

    CrylBa3 is an insecticidal crystal protein revealed by our laboratory. It has high toxicity against Plutel-la xylostella. The object of this research is to find amino acids that are important to its insecticidal activity and to provide a theoretical basis for the research on pesticidal mechanism and recombination of insecticidal proteins. Firstly, the database Pole Bio-Informatique Lyonnais was used to predict the secondary structure of CrylBa3; secondly, hydrophobic regions were found after analyzing the protein sequence of CrylBa3 with the software called BioEdit; finally, 20 amino acid residue sites were determined after multiple alignments between CrylBa3, CrylAal, Cry2Aal, Cry3Aal and Cry4Bal. Over-lapping-PCR was used to make site-directed mutation on CrylBa. Twenty mutants were expressed in Escherichia coli BL21 (DE3) strain respectively, and the bioassays against Plutella xylostella were conducted with the proteins expressed in the mutants. The results showed that 20 mutant proteins could be expressed normally with a molecular weight of 66 ku in BL21 strain and existed as inclusion bodies. Bioas-say results showed that the toxicities of mutant M6 (R192L), M10 (W303A) and M19 (H485G) were decreased significantly. The prediction results of secondary structure of the mutants indicated that the toxin conformation of the mutants whose toxicity decreased sharply was changed markedly. However, neither the toxicity nor the seconda-ry structure of the other 17 mutants was changed obviously. Arginine on site-192, tryptophan on site-303 and histi-dine on site-485 were very important for the toxicity of CrylBa3 against P. xylostella, and the reduction of toxicity was related to the diversification of toxin conformation caused by the mutations of the three amino acid residues.%Cry1Ba3是由本实验室发掘的对小菜蛾有高毒力的杀虫晶体蛋白.为了寻找对杀虫活性有重要影响的氨基酸,为杀虫机理研究和改造杀虫蛋白提供理论

  14. Realized heritability of resistance to dimehypo and cartap in diamondback moth, Plutella xylostella%小菜蛾对杀虫双和杀螟丹抗性的现实遗传力

    Institute of Scientific and Technical Information of China (English)

    程罗根; 李凤良; 韩招久; 李忠英; 陈之浩

    2001-01-01

    利用室内选育119代的小菜蛾Plutella xylostella抗性品系,分析了小菜蛾对杀虫双和杀螟丹抗药性的现实遗传力,并对遗传力和杀虫剂的杀死率对抗性发展速率的影响进行了预测.结果表明,室内继代药剂选择119代后,小菜蛾对杀虫双和杀螟丹抗性的遗传力很低(h2=0.03).因此,小菜蛾对这两种药剂产生更高水平抗性的潜力不大.在选择的前半段(F30),杀虫双和杀螟丹的抗性遗传力(分别为0.14和0.11)高于选择后半段(F80)的遗传力(均为0.05),选择前、后半段的选择差数没有明显差别.即使在室内选择条件下,假如斜率=2.0(δp=0.5),h2=0.05,群体中70%个体致死时要获得10倍的抗性,约需34代.田间条件下,由于等位基因频率的变化、环境变异等因素的影响,抗性增长10倍则需要更长的时间,因此田间条件下小菜蛾在短期内不易对杀虫双和杀螟丹产生高水平抗性.

  15. Tritrophic choice experiments with Bt plants, the diamondback moth (Plutella xylostella) and the parasitoid Cotesia plutellae

    NARCIS (Netherlands)

    Schuler, T.H.; Potting, R.P.J.; Denholm, I.; Clark, S.J.; Clark, A.J.; Stewart, C.N.; Poppy, G.M.

    2003-01-01

    Parasitoids are important natural enemies of many pest species and are used extensively in biological and integrated control programmes. Crop plants transformed to express toxin genes derived from Bacillus thuringiensis (Bt) provide high levels of resistance to certain pest species, which is likely

  16. 小菜蛾对溴氰菊酯抗药性的随机扩增多态性DNA分析%Randomized amplification of polymorphic DNA in near isogenic lines of deltamelthrin-resistant diamond-back moth,Plutella xylostella

    Institute of Scientific and Technical Information of China (English)

    程罗根; 陈之浩; 李凤良; 李忠英; 韩招久

    2003-01-01

    利用室内选育119代的抗溴氰菊酯小菜蛾Plutella xylostella品系和敏感品系,通过反复回交和自交建立近等基因系.用Operon公司合成的20个引物对近等基因系基因组DNA进行PCR扩增.3个引物在抗性品系中分别产生1条特异扩增带,4个引物在敏感品系中分别产生了1~5条特异扩增带.由于在近等基因系中,除了与抗性相关的基因区外,其它的遗传背景是相同的,因此可以认为这些特异带与小菜蛾对溴氰菊酯的抗性有关.

  17. GENOMIC FEATURES OF COTESIA PLUTELLAE POLYDNAVIRUS

    Institute of Scientific and Technical Information of China (English)

    LIUCai-ling; ZHUXiang-xiong; FuWen-jun; ZHAOMu-jun

    2003-01-01

    Polydnavirus was purified from the calyx fluid of Cotesia plutellae ovary. The genomic features of C. plutellae polydnavirus (CpPDV) were investigated. The viral genome consists of at least 12 different segments and the aggregate genome size is a lower estimate of 80kbp. By partial digestion of CpPDV DNA with BamHI and subsequent ligation with BamHI-cut plasmid Bluescript, a representative library of CpPDV genome was obtained.

  18. Antibiosis in Ascia monuste orseis Godart (Lepidoptera: Pieridae ...

    African Journals Online (AJOL)

    Flávio Gonçalves

    In general, throughout the larval stage, A. monuste orseis caterpillars that fed on the .... DC) na biologia Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae). Cienc. ... Plant resistance to arthropods: molecular and conventional approaches.

  19. 1578-IJBCS-Article-Karamoko Diarra

    African Journals Online (AJOL)

    hp

    Laboratory evaluation of toxicity of Bacillus thuringiensis, neem oil and methamidophos against Plutella ... insecticide (methamidophos) on larvae of P. xylostella under ..... properties that inhibits molting, growth and larval development (Patil ...

  20. The production relationship of destruxins and blastospores of Metarhizium anisopliae with virulence againstPlutella xylostella

    Institute of Scientific and Technical Information of China (English)

    DONG Ting-yan; ZHANG Bo-wen; WENG Qun-fang; HU Qiong-bo

    2016-01-01

    Metarhizium anisopliaeas an essential entomopathogenic fungushas been known to produce destruxins (a kind of cyclo-peptidic mycotoxins) and blastospores in submerged culture. Blastospores and destruxins are candidates for in-secticides, but the relations of both productions and the impact factors are unclear yet. In this study, we investigated the effects of inoculums, rotation, dissolved oxygen (DO) on the productions of blastospores and destruxins A and B (DA and DB) in submerged culture ofM. anisopliaestrain MaQ01. The results indicated that DO levels were regulated by inoculum amounts and rotation speeds, meanwhile, the productions of DA, DB and blastospores were also closely inlfuenced by those factors. Totaly, when DO value was more than 40%, the higher productions of destruxins and blastospores were achieved, by contrast, lower than 40% of DO values resulted in lower productions. The regression analysis suggested that the productions of DA, DB and blastospores were positively correlated with the DO levels. Meanwhile, the positive correlations between the productions of DA or DB and blastospores were also found. Brielfy, when the rotation is 150 r min–1 and the inoculum is 1.0×106 spore mL–1, the DA, DB and blastospores achieved the best production of 61.81 mg mL–1, 24.74 mg mL–1 and 5.73×106 spore mL–1, respectively. In addition, the pathogenicities of blastospores and conidia against Plutela xylostela were bioassayed. The higher mortalities of P. xylostela were totaly recorded in blastospore treatments than in conidia treatments, especialy in lower dosages and earlier periods. Our research wil give some new insights to production of destruxins and blastospores by using M. anisopliae.

  1. cDNA cloning and characterization of the carboxylesterase pxCCE016b from the diamondback moth, Plutella xylostella L.

    Institute of Scientific and Technical Information of China (English)

    HU Zhen-di; FENG Xia; LIN Qing-sheng; CHEN Huan-yu; LI Zhen-yu; YIN Fei; LIANG Pei; GAO Xi-wu

    2016-01-01

    Carboxylesterase is a multifunctional superfamily and can be found in almost all living organisms. As the metabolic enzymes, carboxylesterases are involved in insecticides resistance in insects for long time. In our previous studies, the enhanced carboxylesterase activities were found in the chlorantraniliprole resistance strain of diamondback moth (DBM). However, the related enzyme gene of chlorantraniliprole resistance has not been clear in this strain. Here, a ful-length cDNA of carboxylesterasepxCCE016b was cloned and exogenously expressed inEscherichia coliat the ifrst time, which contained a 1693 bp open reading frame (ORF) and encoded a protein of 542 amino acids. Sequence analysis showed that this cDNA has a predicted mass of 61.56 kDa and a theoretical isoelectric point value of 5.78. The sequence of deduced amino acid possessed the classical structural features: a type-B carboxylesterase signature 2 (EDCLYLNVYTK), a type-B carboxylesterase serine active site (FGGDPENITIFGESAG) and the catalytic triad (Ser186, Glu316, and His444). The real-time quantitative PCR (qPCR) analysis showed that the expression level of thepxCCE016b was signiifcantly higher in the chlorantraniliprole resistant strain than in the susceptible strain. Furthermore,pxCCE016b was highly expressed in the midgut and epidermis of the DBM larvae. When the 3rd-instar larvae of resistant DBM were exposed to abamectin, alpha-cypermethrin, chlorantraniliprole, spinosad, chlorfenapyr and indoxacarb insecticides, the up-regulated expression of pxCCE016b was observed only in the group treated by chlorantraniliprole. In addition, recombinant vector pET-pxCCE016b was constructed with the most coding region (1293 bp) and large number of soluble recombinant proteins (less than 48 kDa) were expressed successfuly with prokaryotic cel. Western blot analysis showed that it was coded by pxCCE016b. Al the above ifndings provide important information for further functional study, although we are uncertainty whether the pxCCE016bgene is actualy involved in chlorantraniliprole resistance.

  2. Efficacy of Bacillus thuringiensis (var. kurstaki) Against Diamondback Moth (Plutella xylostella L.) Eggs and Larvae on Cabbage Under Semi-Controlled Greenhouse Conditions

    Science.gov (United States)

    Legwaila, Mitch M.; Munthali, David C.; Kwerepe, Baone C.; Obopile, Motshwari

    2015-01-01

    The efficacy of Bacillus thuringiensis (var. kurstaki) (Btk) against the diamondback moth (DBM) on cabbage was studied at Botswana College of Agriculture, Gaborone, Botswana. Using five concentrations of Btk: 2, 4, 6, 8, and 10 g/L, bioassays were conducted against DBM eggs and second instar larvae at 30°C ± 5°C. Each treatment was replicated three times. Probit analysis was used to determine the LD50 and LD90 values for the treatments against eggs and larvae. When the treatments were assessed at 72, 96, 120, and 144 hours, LD90 values against larvae were 11.02, 10.22, 5.92, and 4.01 g/L, whereas they were 7.71, 6.94, and 6.24 g/L against eggs when assessed 48, 72, and 96 hours after the expected time of hatching. This indicated that Btk was effective against both eggs and larvae when exposed for long periods. The slopes of the probit lines for larvae assessed at 24, 48, 72, 96, 120, and 144 hours after application were 0.250, 1.064, 0.910, 0.383, 0.453, and 0.414, while those against eggs were 1.153, 1.246, and 0.933 when assessed 48, 72, and 96 hours after the expected time of hatching. This indicates a smaller change in mortality with increase in pesticide dosage for both eggs and larvae. Btk treatments achieved 85.7%–94.6% reduction in DBM damage on cabbage. Therefore, Btk can be used to achieve effective control of DBM eggs and larvae and reduce damage on cabbage under greenhouse conditions. PMID:26816488

  3. Impact of botanical extracts derived from Melia azedarach and Azadirachta indica on populations of Plutella xylostella and its natural enemies: a field test of laboratory findings

    NARCIS (Netherlands)

    Charleston, D.S.; Kfir, R.; Dicke, M.; Vet, L.E.M.

    2006-01-01

    Differences between results from ecological laboratory studies and what actually happens in the field can be large. Therefore, field experiments are essential to validate laboratory findings. In previous laboratory trials we investigated the impact of aqueous leaf extracts from the syringa tree,

  4. Impact of botanical extracts derived from Melia azedarach and Azadirachta indica on populations of Plutella xylostella and its natural enemies: A field test of laboratory findings

    NARCIS (Netherlands)

    Charleston, D.S.; Kfir, R.; Dicke, M.; Vet, L.E.M.

    2006-01-01

    Differences between results from ecological laboratory studies and what actually happens in the field can be large. Therefore, field experiments are essential to validate laboratory findings. In previous laboratory trials we investigated the impact of aqueous leaf extracts from the syringa tree,

  5. Impact of botanical extracts derived from Melia azedarach and Azadirachta indica on populations of Plutella xylostella and its natural enemies: A field test of laboratory findings

    NARCIS (Netherlands)

    Charleston, D.S.; Kfir, R.; Dicke, M.; Vet, L.E.M.

    2006-01-01

    Differences between results from ecological laboratory studies and what actually happens in the field can be large. Therefore, field experiments are essential to validate laboratory findings. In previous laboratory trials we investigated the impact of aqueous leaf extracts from the syringa tree, Mel

  6. Larval fish nutrition

    National Research Council Canada - National Science Library

    Holt, J

    2011-01-01

    ... introduction to fish micronutrient history 4.2 Micronutrients in larval feeds 4.3 Requirements versus recommendations 4.4 Vitamins 4.5 Minerals 34.6 Future challenges Section 2: Nutritional Physi...

  7. Larval nervous systems

    DEFF Research Database (Denmark)

    Nielsen, Claus

    2015-01-01

    The apical organ of ciliated larvae of cnidarians and bilaterians is a true larval organ that disappears before or at metamorphosis. It appears to be sensory, probably involved in metamorphosis, but knowledge is scant. The ciliated protostome larvae show ganglia/nerve cords that are retained as t...... common ancestor of the deuterostomes was very similar to the latest common pelago-benthic ancestor of the protostomes as described by the trochaea theory, and that the neural tube of the chordates is morphologically ventral....

  8. First feeding of larval herring

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter; Støttrup, Josianne

    1985-01-01

    The transition period from endogenous to exogenous feeding by larval herring was investigated in the laboratory for four herring stocks in order to evaluate the chances of survival at the time of fiest feeding. Observations on larval activity, feeding and growth were related to amount of yolk, vi...

  9. Drosophila adult and larval pheromones modulate larval food choice.

    Science.gov (United States)

    Farine, Jean-Pierre; Cortot, Jérôme; Ferveur, Jean-François

    2014-06-07

    Insects use chemosensory cues to feed and mate. In Drosophila, the effect of pheromones has been extensively investigated in adults, but rarely in larvae. The colonization of natural food sources by Drosophila buzzatii and Drosophila simulans species may depend on species-specific chemical cues left in the food by larvae and adults. We identified such chemicals in both species and measured their influence on larval food preference and puparation behaviour. We also tested compounds that varied between these species: (i) two larval volatile compounds: hydroxy-3-butanone-2 and phenol (predominant in D. simulans and D. buzzatii, respectively), and (ii) adult cuticular hydrocarbons (CHs). Drosophila buzzatii larvae were rapidly attracted to non-CH adult conspecific cues, whereas D. simulans larvae were strongly repulsed by CHs of the two species and also by phenol. Larval cues from both species generally reduced larval attraction and pupariation on food, which was generally--but not always--low, and rarely reflected larval response. As these larval and adult pheromones specifically influence larval food search and the choice of a pupariation site, they may greatly affect the dispersion and survival of Drosophila species in nature.

  10. Larval development of japanese "conchostracans"

    DEFF Research Database (Denmark)

    Olesen, Jorgen; Fritsch, Martin; Grygier, Mark J.

    2013-01-01

    For comparison with the remarkable larvae of the laevicaudatan (clam shrimp) Lynceus brachyurus, a basic description of the larval sequence of another laevicaudatan branchiopod, the Japanese Lynceus biformis, is provided. Four larval stages have been identified, ranging in size from 258 to 560 mu m...... to the endopod and a change in the form of the naupliar process, used for food manipulation, from a long, unbranched, pointed spine to a bifid structure. In addition, buds of trunk limbs (five pairs) first appear externally in stage 4 but can be recognized through the cuticle in the previous stage. The larval...

  11. Kauri seeds and larval somersaults

    DEFF Research Database (Denmark)

    Dupont, Steen Thorleif

    2012-01-01

    The trunk morphology of the larvae of the kauri pine (Agathis) seed infesting moth Agathiphaga is described using conventional, polarization, and scanning electron microscopy. The pine seed chamber formed by the larva is also described and commented on. The simple larval chaetotaxy includes more...... of the minute posture sensing setae, proprioceptors, than expected from the lepidopteran larval ground plan. The excess of proprioceptors is suggested to be necessary for sensory input concerning the larval posture within the seed chamber. The trunk musculature includes an autapomorphic radial ventral...... musculature made up of unique multisegmental muscles. The combined presence of additional proprioceptors and the unique ventral musculature is proposed to be related to the larval movement within the confined space of the seed chamber, especially to a proposed somersault movement that allows the larva...

  12. Identification and Characterization of Pheromone Receptors and Interplay between Receptors and Pheromone Binding Proteins in the Diamondback Moth, Plutella xyllostella

    OpenAIRE

    Sun, Mengjing; Liu, Yang; Walker, William B.; Liu, Chengcheng; Lin, Kejian; Gu, Shaohua; ZHANG Yongjun; Zhou, Jingjiang; Wang, Guirong

    2013-01-01

    Moths depend on olfactory cues such as sex pheromones to find and recognize mating partners. Pheromone receptors (PRs) and Pheromone binding proteins (PBPs) are thought to be associated with olfactory signal transduction of pheromonal compounds in peripheral olfactory reception. Here six candidate pheromone receptor genes in the diamondback moth, Plutella xyllostella were identified and cloned. All of the six candidate PR genes display male-biased expression, which is a typical characteristic...

  13. Effects of Barbarea vulgaris on the development and oviposition preference of Plutella xylostella%欧洲山芥对小菜蛾个体发育及产卵选择性的影响

    Institute of Scientific and Technical Information of China (English)

    吕建华; 刘树生

    2006-01-01

    测试了欧洲山芥对小菜蛾个体发育和成虫繁殖力的影响,以及小菜蛾雌蛾经历不同植物后对其产卵选择性的影响.结果表明,在欧洲山芥开花结籽期植株上取食发育至化蛹的少量个体,与白菜、结球甘蓝上取食发育的个体相比,身体较小,繁殖力较低;欧洲山芥具有刺激小菜蛾成虫增加生殖力的作用,对甘蓝上发育出来的雌成虫,当分别提供欧洲山芥或结球甘蓝让其产卵时,在两种植物上平均每雌产卵量分别为267粒和139粒;经历不能明显改变小菜蛾雌成虫对欧洲山芥的强烈嗜好性,当小菜蛾在成虫期经历白菜或甘蓝后,对这两种植物的相对嗜好性虽有所提高,但仍将绝大部分或所有的卵产在欧洲山芥上.可见,欧洲山芥对于小菜蛾是一种较为理想的诱杀植物.

  14. Effects of host plant and avermectin on oviposition preference of diamondback moth, Plutella xylostella L.%寄主种类和阿维菌素对小菜蛾产卵选择行为的影响

    Institute of Scientific and Technical Information of China (English)

    闫喜中; 孙学俊; 邓彩萍; 张晓飞; 郝赤

    2014-01-01

    通过田间笼罩试验,研究了小菜蛾对7种十字花科蔬菜的产卵选择性,以及喷施阿维菌素对小菜蛾产卵选择行为的影响.结果发现,其选择顺序为小白菜>油菜>芥菜>萝卜>菜心>甘蓝>花椰菜;喷施阿维菌素之后,小菜蛾对寄主的产卵选择性发生了变化,其在尽可能的躲避杀虫剂后才选择喜好的寄主植物.可见,寄主种类和阿维菌素共同影响小菜蛾的产卵选择行为.

  15. 几种生物农药对小菜蛾的室内毒力和田间药效%Laboratory determination of bioactivity of some biological pesticides against Plutella xylostella and their control effects in fields

    Institute of Scientific and Technical Information of China (English)

    陈若霞; 柴伟纲; 王扬军; 周金波; 谌江华; 姚红燕

    2007-01-01

    室内和田间试验表明,三令对小菜蛾2龄幼虫的毒力较高,LC50为0.005 0 mg/L,是常用药剂灭虫灵的1.11倍,三令1 500倍药后3 d防效为72.87%,药后7 d达81.79%,起效快,药效好,可作小菜蛾高发期的主要药剂应用."Delfin"Bt、生绿Bt、锐星Bt对小菜蛾2龄幼虫的室内毒力也较高,LC50在0.003 4~0.026 9 IU/mg,为福建Bt的2.95~23.25倍,"Delfin"Bt 1 500倍、生绿Bt 750倍、锐星Bt 750倍药后3 d防效为53.49%~59.60%,药后7 d达70.79%~78.36%,药后13 d仍有55.28%~63.31%,药效平稳,持效期较长,可以用于小菜蛾防治.此外,大印1 000倍药后3 d防效70.94%,药后7 d 74.40%,药后13 d 61.26%,起效较快,持效性较好,可作为搭配药剂应用.菜喜1 000倍药后3 d防效为75.94%,药后7 d 59.50%,起效较快,持效期短,比较适宜在临近收获期前使用.

  16. Studies on Analysis of the Genetic and Evolution of the Plutella xylostella (L.) from Different Populations%小菜蛾种群抗性分子遗传与进化分析

    Institute of Scientific and Technical Information of China (English)

    李瑄; 乔传令

    2000-01-01

    The high resistant larvae of diamondback moth (DBM)were collected from 4 differe nt populations. The analysis results by GENEPOP software showed that the hypothe sis of Hardy-Weinberg equilibrium was rejected. There was systemic heterozygote deficit in these populations and existed genetic mutation in four populations. The results from esterase of Beijing diamondback moth suggested that the gene fl ow of the diamondback moth was due to the vegetables transportation with high fr equency.

  17. 一株新型Bt菌株的鉴定及其抗椰子茎泻血病菌和杀小菜蛾活性%Identification of Bacillus thuringiensis Against Both Plutella xylostella and Stem Bleeding of Coconut

    Institute of Scientific and Technical Information of China (English)

    孙晓东; 余凤玉; 宋薇薇; 牛晓庆; 覃伟权

    2015-01-01

    从海南采集的土样中分离鉴定获得1株可抑制椰子茎泻血病菌和杀小菜蛾幼虫的苏云金芽孢杆菌(Bacillus thuringiensis,简称Bt)WENCHANG-BT20;经cry基因的鉴定明确了该菌株含有cry1Aa、cry1La、cry1Ai、cry1Ac、cry1Be、cry1Ka、cry1Ia、cry2Ab基因.生物学检测结果表明,该菌株晶体蛋白对小菜蛾幼虫的LC50为0.088 μg/mL(95%置信区间为0.046~0.127 μg/mL);该菌株对椰子茎泻血病菌菌丝生长有一定的抑制作用,平板对峙培养法培养5d后,抑菌圈直径为22 mm.

  18. 印楝素作用下小菜蛾体内MFO和JHE活力的变化%Changes of JHE and MFO Activity in Body of Plutella xylostella under Neem Treating

    Institute of Scientific and Technical Information of China (English)

    王娟; 戴华国; 李洪山

    2006-01-01

    试验结果表明,3种不同印楝素用量作用下的小菜蛾体内保幼激素滴度在36h时都明显高于对照.3种用量作用下的O-脱甲基酶活力都受到抑制,变化趋势基本一致,但变幅不同;高用量(LC50、LC80)印楝素能抑制小菜蛾体内N-脱甲基酶的活力.在LC50、LC80用量作用下,保幼激素滴度变化与O-或N-脱甲基酶活力变化有一定的相随性.

  19. Bioactivity of methanol extracts from Justicia procumbens against Plutella xylostella%爵床的甲醇提取物对小菜蛾的生物活性作用

    Institute of Scientific and Technical Information of China (English)

    郭明程; 李保同; 汤丽梅; 李晓花; 梁同军

    2015-01-01

    为探明爵床(Justicia procumbens)甲醇提取物对小菜蛾的生物活性,采用室内生测法测定了爵床甲醇提取物对小菜蛾的触杀、拒食、胃毒、生长发育抑制和产卵忌避作用.结果表明,爵床甲醇提取物对小菜蛾幼虫具有较强的触杀、拒食、胃毒和生长发育抑制活性,对小菜蛾成虫具有较强的产卵忌避活性.在触杀试验中,药后1、2d和3d爵床甲醇提取物对小菜蛾3龄幼虫的致死中浓度(LC50)分别为5.17、4.05和3.06 mg/mL;在拒食试验中,药后1d和2d提取物对3龄幼虫的选择性拒食中浓度(AFC50)分别为2.64和3.13 mg/mL,药后1d和2d提取物对3龄幼虫的非选择性拒食中浓度(AFC50)分别为3.70、4.54 mg/mL;在胃毒试验中,药后4、5、6d和7d提取物对3龄幼虫的致死中浓度(LC50)分别为8.13、3.65、2.88、2.23 mg/mL;在生长发育抑制试验中,药后1d和2d提取物对3龄幼虫的抑制中浓度(IC50)分别为2.02、1.40 mg/mL;在产卵忌避试验中,药后1、2d和3d提取物对小菜蛾成虫的选择性产卵忌避中浓度(AOC50)分别为2.61、3.66、4.58 mg/mL,药后1、2和3d提取物对小菜蛾成虫的非选择性产卵忌避中浓度(AOC50)分别为3.19、4.52、5.65 mg/mL.由此证实,爵床提取物对小菜蛾具有显著的毒杀活性,具有开发为新型高效、低毒植物源农药的潜在价值.

  20. Control Effects of Pyridalyl 10% EC on Plutella xylostella L.%10%三氟甲吡醚乳油防治小菜蛾田间药效试验

    Institute of Scientific and Technical Information of China (English)

    赖宝春; 魏秀永

    2008-01-01

    试验结果表明:10%三氟甲吡醚EC对小菜蛾防治效果优良,使用150.0 g a.I./hm2和112.5 g a.I./hm2处理,在施药后3d的防效分别为91.58%、89.46%,10d达到96.81%、95.94%,均明显高于对照药剂2%甲氨基阿维菌素苯甲酸盐EC、5%氟虫腈SC和2.5%溴氰菊酯EC的防效.建议生产上推广使用10%三氟甲吡醚EC 112.5 g a.I./hm2.

  1. Field Trial of Azadirachtin 0.7% (EC) Against Pieris rapae L and Plutella xylostella L%0.7%印楝素乳油防治小菜蛾、菜青虫田间药效试验

    Institute of Scientific and Technical Information of China (English)

    靳然; 侯毅; 李生才; 韩巨才

    2007-01-01

    试验了0.7%印楝素乳油田间防治小菜蛾、菜青虫的药效.结果表明:0.7%印楝素乳油2.1~4.2 g(a.i.)/hm2对菜青虫进行防治,药后7d防效达80%以上,具有较好防治效果,建议在生产上的使用剂量为3.15~4.2 g(a.i.)/hm2.0.7%印楝素乳油3.15~5.25 g(a.i.)/hm2防治小菜蛾,药后7 d防效达90%以上,可有效控制其危害,建议在生产上的使用剂量为4~5 g(a.i.)/hm2.

  2. Influence of plant extracts on the pupation rate and pupal weight of Plutella xylostella%植物提取物对小菜蛾化蛹率和蛹重的影响

    Institute of Scientific and Technical Information of China (English)

    魏辉; 尤民生; 王前梁; 侯有明; 林泽燕

    2004-01-01

    分别用35种植物乙醇提取物处理的叶片饲养小菜蛾幼虫,研究非嗜食植物提取物对小菜蛾化蛹率和蛹重的影响.研究表明,茶枯(Camellia oleifera)、番石榴(Psidium guajava)、飞扬草(Euphorbia hirta)、南洋楹(Albizia falcataria)、薄荷(Mentha haplocalyx)、蓖麻(Ricinus communis)、假连翘(Duranta repens)的乙醇提取物对小菜蛾化蛹有显著的抑制作用(P<0.01,DMRT),化蛹率都低于30.00%;从蛹重来看,经积雪草(Centella asiatica)、芒果(Mangifera indica)、构树(Broussonetia papyrifera)、细叶桉(Eucalyptus tereticornis)的乙醇提取物处理,小菜蛾蛹重显著减轻(P<0.01,DMRT),蛹重(10只蛹)都低于0.0300g.

  3. Biochemical genetic mechanisms of resistance to dimehypo and cartap in diamondback moth, Plutella xylostella L%小菜蛾对杀虫双和杀螟丹抗性的生化遗传分析

    Institute of Scientific and Technical Information of China (English)

    程罗根; 陈之浩; 李凤良; 李忠英

    2003-01-01

    @@ 在对室内杀虫双和杀螟丹继代选择过程中小菜蛾的抗性发展变化、抗性生化机制、抗性遗传方式和抗性风险评估的基础上,笔者测定了小菜蛾抗杀虫双品系、抗杀螟丹品系和敏感品系及其杂交后代的生物学特性以及蛹的酶活性,通过t值检验酶活性间的差异显著性,从生物统计学和遗传学角度分析酶活性与抗性之间的关系.

  4. 小菜蛾对杀螟丹抗性相关序列的代表性差异分析%Representational Difference Analysis of DNA Sequences Related to Cartap Resistance in Diamondback Moth,Plutella xylostella L.

    Institute of Scientific and Technical Information of China (English)

    程罗根; 陈之浩; 张晓飞; 李忠英

    2003-01-01

    采用代表性差异分析方法,以小菜蛾的敏感品系作为驱赶扩增子,抗杀螟丹近等基因系作为检测扩增子,通过3轮消减杂交得到大小为150~300bp的差异片段,经亚克隆测序并与GenBank等数据库同源比较,发现其中一个亚克隆序列与P450基因有部分同源性,其余亚克隆与已知基因序列的同源性较低,判断这些序列可能是新基因的片段.

  5. NCBI nr-aa BLAST: CBRC-AGAM-05-0031 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-05-0031 ref|NP_068292.1| PxORF73 peptide [Plutella xylostella granuloviru...s] gb|AAG27371.1|AF270937_73 PxORF73 peptide [Plutella xylostella granulovirus] NP_068292.1 2e-15 42% ...

  6. NCBI nr-aa BLAST: CBRC-EEUR-01-0896 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-EEUR-01-0896 ref|NP_068292.1| PxORF73 peptide [Plutella xylostella granuloviru...s] gb|AAG27371.1|AF270937_73 PxORF73 peptide [Plutella xylostella granulovirus] NP_068292.1 0.002 33% ...

  7. NCBI nr-aa BLAST: CBRC-TGUT-37-0032 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TGUT-37-0032 ref|YP_758557.1| hypothetical protein PXMNV_gp091 [Plutella xylostella multiple... nucleopolyhedrovirus] gb|ABE68476.1| unknown [Plutella xylostella multiple nucleopolyhedrovirus] YP_758557.1 2e-19 42% ...

  8. NCBI nr-aa BLAST: CBRC-TGUT-37-0314 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TGUT-37-0314 ref|YP_758557.1| hypothetical protein PXMNV_gp091 [Plutella xylostella multiple... nucleopolyhedrovirus] gb|ABE68476.1| unknown [Plutella xylostella multiple nucleopolyhedrovirus] YP_758557.1 2e-07 33% ...

  9. NCBI nr-aa BLAST: CBRC-HSAP-10-0003 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-HSAP-10-0003 ref|YP_758557.1| hypothetical protein PXMNV_gp091 [Plutella xylostella multiple... nucleopolyhedrovirus] gb|ABE68476.1| unknown [Plutella xylostella multiple nucleopolyhedrovirus] YP_758557.1 1e-13 38% ...

  10. NCBI nr-aa BLAST: CBRC-RMAC-09-0029 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-RMAC-09-0029 ref|YP_758557.1| hypothetical protein PXMNV_gp091 [Plutella xylostella multiple... nucleopolyhedrovirus] gb|ABE68476.1| unknown [Plutella xylostella multiple nucleopolyhedrovirus] YP_758557.1 7e-07 37% ...

  11. Estimating of larval stadia of West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) developed in the artificial larval diet by measuring larval head widths.

    OpenAIRE

    下地, 幸夫; Shimoji, Yukio; 琉球産経株式会社

    2003-01-01

    The survey conducted by measuring larval head widths of West Indian sweetpotato weevil Euscepes postfasciatus developed in the artificial larval diet revealed that there were five larval stadia in the developmental period. The result of this experiment can be used to estimate the larval stadia approximately in the artificial larval diet.

  12. TOXICITY OF INSECTICIDES COMMONLY USED IN VEGETABLE FIELDS TO THE DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA, AND ITS PARASITE, COTESIA PLUTELLAE%菜田常用杀虫剂对小菜蛾及菜蛾绒茧蜂的选择毒杀作用

    Institute of Scientific and Technical Information of China (English)

    施祖华; 刘树生

    1998-01-01

    在室内测定了9种菜田常用杀虫剂对小菜蛾幼虫及其主要天敌菜蛾绒茧蜂成虫和茧的毒性.结果表明,应用厂家推荐田间防治小菜蛾的使用浓度,对小菜蛾的杀虫效果锐劲特、Bt、虫螨光可达100%,生物复合病毒杀虫剂、宝路和抑太保可达95%以上,杀虫双达80%,而氰戊菊酯和万灵对小菜蛾的杀虫效果较差,供试幼虫最终化蛹率分别达70.0%和78.3%.让菜蛾绒茧蜂成虫接触厂家推荐浓度的药膜,接触杀虫双2小时后的死亡率即达80%以上;12小时后,接触锐劲特的死亡率即达100%;24小时后,接触万灵和杀虫双的累计死亡率达90%以上,接触宝路和氰戊菊酯的约50%,而接触抑太保、Bt、虫螨光和生物复合病毒杀虫剂的累计死亡率均在20%以下,和对照无显著差异.作者认为在菜蛾绒茧蜂等天敌较为丰富的季节,虫螨光、Bt、生物复合病毒杀虫剂、宝路和抑太保应属防治小菜蛾优先选用的杀虫剂,锐劲特则主要应在小菜蛾大发生、而天敌又很少时应用.

  13. First feeding of larval herring

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter; Støttrup, Josianne

    1985-01-01

    The transition period from endogenous to exogenous feeding by larval herring was investigated in the laboratory for four herring stocks in order to evaluate the chances of survival at the time of fiest feeding. Observations on larval activity, feeding and growth were related to amount of yolk......, visual experience with potential prey organisms prior to first feeding and prey density. Herring larvae did not initiate exogenous feeding until around the time of yolk resorption. The timing of first feeding was not influenced by prior exposure to potential prey organisms during the yolk sac stage....... In the light of these observations, the ecological significance of the yolk sac stage is discussed. Initiation of exogenous feeding was delayed by 1-4 days at a low (7.5 nauplii .cntdot. l-1) compared to a high (120 nauplii .cntdot. l-1) prey density, but even at prey densities corresponding to the lower end...

  14. 'Peer pressure' in larval Drosophila?

    Science.gov (United States)

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-06-06

    Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on 'peer pressure', that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila.

  15. Manipulating the attractiveness and suitability of hosts for diamondback moth (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Badenes-Perez, Francisco R; Nault, Brian A; Shelton, Anthony M

    2005-06-01

    Ovipositional preference and larval survival of the diamondback moth, Plutella xylostella (L.), were compared among cabbage, Brassica oleracea L. variety capitata; glossy collards, Brassica oleracea L. variety acephala; and yellow rocket, Barbarea vulgaris (R. Br.) variety arcuata in different treatments of planting density, host plant age, intercropping, and water stress in 2003 and 2004. P. xylostella laid nearly twice as many eggs per plant in the high planting densities of glossy collards and yellow rocket than in the standard planting densities. Ovipositional preference was positively correlated with plant age in cabbage, glossy collards, and yellow rocket. Larval survival on cabbage was 1.9 times higher on 6-wk than on 12-wk-old plants, whereas larval survival on collards was 12.1 times higher on the younger plants. No larvae survived on either 6- or 12-wk-old yellow rocket plants. Intercropping cabbage with either tomato, Lycopersicon esculentum Mill., or fava bean, Vicia fava L., did not reduce the number of eggs laid on cabbage. No significant differences in oviposition were found between water-stressed and well-irrigated host plants treatments. Yet, P. xylostella larval survival on water-stressed cabbage was 2.1 times lower than on well-irrigated cabbage plants. Based on our findings, the effectiveness of trap crops of glossy collards and yellow rocket could be enhanced by integrating the use of higher planting densities in the trap crop than in the main crop and seeding of the trap crop earlier than the main crop.

  16. Synthesis and Insecticidal Activity of Enzyme-Triggered Functionalized Hollow Mesoporous Silica for Controlled Release.

    Science.gov (United States)

    Kaziem, Amir E; Gao, Yunhao; He, Shun; Li, Jianhong

    2017-09-13

    In the present study, enzymatic responsive controlled release formulations (CRFs) were fabricated. The CRFs were achieved by anchoring mechanically interlocked molecules using α-cyclodextrin onto the surface pore rims of hollow mesoporous silica (HMS). The CRFs were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The results showed that the CRFs had extraordinary loading ability for chlorantraniliprole (42% w/w) and could effectively preserve chlorantraniliprole against degradation under thermal conditions and UV radiation. The CRFs have been proven to be enzyme-sensitive. The release ratio of chlorantraniliprole from CRFs can be accelerated observably when external α-amylase was introduced. The persistence of CRFs was evaluated by regular sampling feeding experiment using Plutella xylostella as the target insect. The results showed that the larval mortality of P. xylostella was much higher than that of Coragen under all concentrations after 14 days, which proved that CRFs had remarkable persistence.

  17. Parasitised caterpillars suffer reduced predation: potential implications for intra-guild predation.

    Science.gov (United States)

    Chen, Wen-Bin; Vasseur, Liette; You, Min-Sheng; Li, Jian-Yu; Wang, Cheng-Xiang; Meng, Ruo-Xue; Gurr, Geoff M

    2017-02-23

    Intra-guild predation (IGP) is an important phenomenon structuring ecological communities and affects the success of biological control. Here we show that parasitism by the koinobiont wasp Cotesia vestalis is associated with behavioural changes in its larval host (diamondback moth, Plutella xylostella) that reduce risk of IGP. Compared with unparasitised caterpillars, parasitised P. xylostella moved less frequently to new feeding patches on plants and were less likely to fall from the plant. Wolf spiders killed significantly fewer parasitised larvae. Reflecting their reduced movement and capacity to select plant tissue of optimal quality, parasitised caterpillars fed at a lower rate and exhibited delayed development suggesting a trade-off between IGP avoidance and nutrient intake by the host. This change in behaviour to reduce risk may cascade to the first trophic level and help explain the stability of IGP systems.

  18. [Canine peritoneal larval cestodosis caused by Mesocestoides spp. larval stages].

    Science.gov (United States)

    Häußler, T C; Peppler, C; Schmitz, S; Bauer, C; Hirzmann, J; Kramer, M

    2016-01-01

    In a female dog with unspecific clinical symptoms, sonography detected a hyperechoic mass in the middle abdomen and blood analysis a middle grade systemic inflammatory reaction. Laparotomy revealed a peritoneal larval cestodosis (PLC). The diagnosis of an infection with tetrathyridia of Mesocestoides spp. was confirmed by parasitological examination and molecularbiological analysis. Reduction of the intra-abdominal parasitic load as well as a high dose administration of fenbendazole over 3 months led to a successful treatment which could be documented sonographically and by decreased concentrations of C-reactive protein (CRP). Seven months after discontinuation of fenbendazole administration, PLC recurred, pre-empted by an elevation of serum CRP values. According to the literature a life-long fenbendazole treatment was initiated. In cases of unclear chronic granulomatous inflammations in the abdominal cavity in dogs, PLC should be considered. CRP concentration and sonographic examinations are suitable to control for treatment success and a possibly occurring relapse.

  19. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    a reduction in size, caused by crowding, virtually nothing is known about longer-lasting effects after transmission to the definitive host. This study is the first to use in vitro cultivation with feeding of adult trematodes to investigate how numbers of parasites in the intermediate host affect the size......Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer...... and fecundity of adult parasites. For this purpose, we examined two different infracommunities of parasites in crustacean hosts. Firstly, we used experimental infections of Maritrema novaezealandensis in the amphipod, Paracalliope novizealandiae, to investigate potential density-dependent effects in single...

  20. Uji Aktivitas Beberapa Konsentasi Ekstrak Daun dan Buah Mengkudu (Morinda citrifolia L.) Terhadap Ulat Tritip Plutella xyU>stella L. (Lepidoptera : Plutellidae) Di Laboratorium

    OpenAIRE

    Ginting, Maria

    2012-01-01

    This research is aim to to know activity from leaf extract and mengkudu fruit (M L citrifolia.) to tritip caterpillar ( P. xylostella L.). This Research is executed on Laboratory Pest Plant Faculty Of Agriculture University North Sumatra with height + 25 metre highland and was done on April - May 2005. This research use Factorial Complete Random Device with 2 Factor that is DB (Extract Leaf and Mengkudu fruit) and K ( Concentration). Consist with 6 treatment and 4 replicates. That is...

  1. Behavioral ecology of larval dragonflies and damselflies.

    Science.gov (United States)

    Johnson, D M

    1991-01-01

    During the past decade, larval dragonflies and damselflies (Insecta: Odonata) have been the subjects for very productive ecological research. Descriptive field work, enclosure experiments and laboratory behavior studies have identified fish predation, intraguild predation (especially mutual predation among odonates, including cannibalism) and interference competition as particularly strong interactions influencing larval odonate assemblages. Behavioral differences among species suggest evolutionary adaptations for coexistence with different predators, and for winning intraspecific aggressive encounters.

  2. Detecting larval export from marine reserves.

    Science.gov (United States)

    Pelc, R A; Warner, R R; Gaines, S D; Paris, C B

    2010-10-26

    Marine reserve theory suggests that where large, productive populations are protected within no-take marine reserves, fished areas outside reserves will benefit through the spillover of larvae produced in the reserves. However, empirical evidence for larval export has been sparse. Here we use a simple idealized coastline model to estimate the expected magnitude and spatial scale of larval export from no-take marine reserves across a range of reserve sizes and larval dispersal scales. Results suggest that, given the magnitude of increased production typically found in marine reserves, benefits from larval export are nearly always large enough to offset increased mortality outside marine reserves due to displaced fishing effort. However, the proportional increase in recruitment at sites outside reserves is typically small, particularly for species with long-distance (on the order of hundreds of kilometers) larval dispersal distances, making it very difficult to detect in field studies. Enhanced recruitment due to export may be detected by sampling several sites at an appropriate range of distances from reserves or at sites downcurrent of reserves in systems with directional dispersal. A review of existing empirical evidence confirms the model's suggestion that detecting export may be difficult without an exceptionally large differential in production, short-distance larval dispersal relative to reserve size, directional dispersal, or a sampling scheme that encompasses a broad range of distances from the reserves.

  3. Metacommunity patterns in larval odonates.

    Science.gov (United States)

    McCauley, Shannon J; Davis, Christopher J; Relyea, Rick A; Yurewicz, Kerry L; Skelly, David K; Werner, Earl E

    2008-11-01

    The growth of metacommunity ecology as a subdiscipline has increased interest in how processes at different spatial scales structure communities. However, there is still a significant knowledge gap with respect to relating the action of niche- and dispersal-assembly mechanisms to observed species distributions across gradients. Surveys of the larval dragonfly community (Odonata: Anisoptera) in 57 lakes and ponds in southeast Michigan were used to evaluate hypotheses about the processes regulating community structure in this system. We considered the roles of both niche- and dispersal-assembly processes in determining patterns of species richness and composition across a habitat gradient involving changes in the extent of habitat permanence, canopy cover, area, and top predator type. We compared observed richness patterns and species distributions in this system to patterns predicted by four general community models: species sorting related to adaptive trade-offs, a developmental constraints hypothesis, dispersal assembly, and a neutral community assemblage. Our results supported neither the developmental constraints nor the neutral-assemblage models. Observed patterns of richness and species distributions were consistent with patterns expected when adaptive tradeoffs and dispersal-assembly mechanisms affect community structure. Adaptive trade-offs appeared to be important in limiting the distributions of species which segregate across the habitat gradient. However, dispersal was important in shaping the distributions of species that utilize habitats with a broad range of hydroperiods and alternative top predator types. Our results also suggest that the relative importance of these mechanisms may change across this habitat gradient and that a metacommunity perspective which incorporates both niche- and dispersal-assembly processes is necessary to understand how communities are organized.

  4. Anopheline larval habitats seasonality and species distribution: a prerequisite for effective targeted larval habitats control programmes.

    Directory of Open Access Journals (Sweden)

    Eliningaya J Kweka

    Full Text Available BACKGROUND: Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya. METHODS AND FINDINGS: A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60% and An.arabiensis (18.34%, the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024 and An. arabiensis (P = 0.002 larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001, grass cover (P≤0.001, while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001. The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001 when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002. When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines. CONCLUSION: These findings suggest that implementation of effective larval

  5. Rehydration of forensically important larval Diptera specimens.

    Science.gov (United States)

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  6. Study of the biology of Trichogramma chilonis Ishii (Hymenoptera ...

    African Journals Online (AJOL)

    user1

    KEYWORDS: Trichogramma chilonis, Maruca vitrata, biology, Plutella xylostella ... Egg parasitoids play an important role in the control of lepidopterous pests. (Li, 1994). ..... I am also grateful to Mr D. Abeeluck, Principal Research Scientist of.

  7. Adaptation to larval crowding in Drosophila ananassae and Drosophila nasuta nasuta : increased larval competitive ability without increased larval feeding rate

    Indian Academy of Sciences (India)

    ARCHANA NAGARAJAN; SHARMILA BHARATHI NATARAJAN; MOHAN JAYARAM; ANANDA THAMMANNA; SUDARSHAN CHARI; JOY BOSE; SHREYAS V. JOIS; AMITABH JOSHI

    2016-06-01

    The standard view of adaptation to larval crowding in fruitflies, built on results from 25 years of multiple experimental evo-lution studies onDrosophila melanogaster , was that enhanced competitive ability evolves primarily through increased larvalfeeding and foraging rate, and increased larval tolerance to nitrogenous wastes, at the cost of efficiency of food conversion tobiomass. These results were at odds from the predictions of classicalK -selection theory, notably the expectation that selec-tion at high density should result in the increase of efficiency of conversion of food to biomass, and were better interpretedthrough the lens of α -selection. We show here that populations ofD. ananassaeandD. n. nasutasubjected to extreme larvalcrowding evolve greater competitive ability and pre-adult survivorship at high density, primarily through a combination ofreduced larval duration, faster attainment of minimum critical size for pupation, greater time efficiency of food conversion tobiomass and increased pupation height, with a relatively small role of increased urea/ammonia tolerance, if at all. This is avery different suite of traits than that seen to evolve under similar selection inD .melanogaster ,andseemstobeclosertotheexpectations from the canonical theory ofK -selection. We also discuss possible reasons for these differences in results acrossthe three species. Overall, the results reinforce the view that our understanding of the evolution of competitive ability in fruit-flies needs to be more nuanced than before, with an appreciation that there may be multiple evolutionary routes through whichhigher competitive ability can be attained.

  8. Experimental analysis of the influence of pest management practice on the efficacy of an endemic arthropod natural enemy complex of the diamondback moth.

    Science.gov (United States)

    Furlong, Michael J; Shi, Zu-Hua; Liu, Yin-Quan; Guo, Shi-Jian; Lu, Yao-Bin; Liu, Shu-Sheng; Zalucki, Myron P

    2004-12-01

    Maximizing the contribution of endemic natural enemies to integrated pest management (IPM), programs requires a detailed knowledge of their interactions with the target pest. This experimental field study evaluated the impact of the endemic natural enemy complex of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) on pest populations in commercial cabbage crops in southeastern Queensland, Australia. Management data were used to score pest management practices at experimental sites on independent Brassica farms practicing a range of pest management strategies, and mechanical methods of natural enemy exclusion were used to assess the impact of natural enemies on introduced cohorts of P. xylostella at each site. Natural enemy impact was greatest at sites adopting IPM and least at sites practicing conventional pest management strategies. At IPM sites, the contribution of natural enemies to P. xylostella mortality permitted the cultivation of marketable crops with no yield loss but with a substantial reduction in insecticide inputs. Three species of larval parasitoids (Diadegma semiclausum Hellén [Hymenoptera: Ichneumonidae], Apanteles ippeus Nixon [Hymenoptera: Braconidae], and Oomyzus sokolowskii Kurdjumov [Hymenoptera: Eulophidae]) and one species of pupal parasitoid Diadromus collaris Gravenhorst (Hymenoptera: Ichneumonidae) attacked immature P. xylostella. The most abundant groups of predatory arthropods caught in pitfall traps were Araneae (Lycosidae) > Coleoptera (Carabidae, Coccinelidae, Staphylinidae) > Neuroptera (Chrysopidae) > Formicidae, whereas on crop foliage Araneae (Clubionidae, Oxyopidae) > Coleoptera (Coccinelidae) > Neuroptera (Chrysopidae) were most common. The abundance and diversity of natural enemies was greatest at sites that adopted IPM, correlating greater P. xylostella mortality at these sites. The efficacy of the natural enemy complex to pest mortality under different pest management regimes and appropriate strategies to optimize this

  9. Larval development of Evermannia zosterura (Perciformes: Gobiidae)

    OpenAIRE

    González-Navarro, Enrique; Saldierna-Martínez, Ricardo Javier; Aceves-Medina, Gerardo

    2013-01-01

    Gobiidae is the most specious fish family in the world with almost 2 000 species, however only 11% of them have been described for their larval stages. The entire life cycle information is essential to understand the biology and ecology of this important fish group. Previous studies on zooplankton samples from Ensenada de La Paz, México, have shown the presence of several Gobiidae larvae and juveniles which were identified as Evermania zosterura. The main objective of this work was to describ...

  10. ‘Peer pressure’ in larval Drosophila?

    Directory of Open Access Journals (Sweden)

    Thomas Niewalda

    2014-06-01

    Full Text Available Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on ‘peer pressure’, that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i by the level of innate olfactory preference in the surrounding group nor (ii by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii by the level of innate olfactory preference of the surrounding group nor (iv by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila.

  11. Evolution of increased larval competitive ability in Drosophila melanogaster without increased larval feeding rate

    Indian Academy of Sciences (India)

    MANASWINI SARANGI; ARCHANA NAGARAJAN; SNIGDHADIP DEY; JOY BOSE; AMITABH JOSHI

    2016-09-01

    Multiple experimental evolution studies on Drosophila melanogasterin the 1980s and 1990s indicated that enhanced competitive ability evolved primarily through increased larval tolerance to nitrogenous wastes and increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and this became the widely accepted view of how adaptation to larval crowding evolves in fruitflies. We recently showed that populations of D. ananassaeand D. n. nasuta subjected to extreme larval crowding evolved greater competitive ability without evolving higher feeding rates, primarily through acombination of reduced larval duration, faster attainment of minimum critical size for pupation, greater efficiency of food conversion to biomass, increased pupation height and, perhaps, greater urea/ammonia tolerance. This was a very differentsuite of traits than that seen to evolve under similar selection in D. melanogasterand was closer to the expectations from the theory of K-selection. At that time, we suggested two possible reasons for the differences in the phenotypic correlates ofgreater competitive ability seen in the studies with D. melanogaster and the other two species. First, that D. ananassae and D. n. nasuta had a very different genetic architecture of traits affecting competitive ability compared to the long-term labora-tory populations of D. melanogaster used in the earlier studies, either because the populations of the former two species were relatively recently wild-caught, or by virtue of being different species. Second, that the different evolutionary trajectories in D. ananassae and D. n. nasuta versus D. melanogaster were a reflection of differences in the manner in which larval crowding was imposed in the two sets of selection experiments. The D. melanogaster studies used a higher absolute density of eggs per unit volume of food, and a substantially larger total volume of food, than the studies on D. ananassae and D. n. nasuta. Here, we

  12. Evolution of increased larval competitive ability in Drosophila melanogaster without increased larval feeding rate.

    Science.gov (United States)

    Sarangi, Manaswini; Nagarajan, Archana; Dey, Snigdhadip; Bose, Joy; Joshi, Amitabh

    2016-09-01

    Multiple experimental evolution studies on Drosophila melanogaster in the 1980s and 1990s indicated that enhanced competitive ability evolved primarily through increased larval tolerance to nitrogenous wastes and increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and this became the widely accepted view of how adaptation to larval crowding evolves in fruitflies.We recently showed that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolved greater competitive ability without evolving higher feeding rates, primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater efficiency of food conversion to biomass, increased pupation height and, perhaps, greater urea/ammonia tolerance. This was a very different suite of traits than that seen to evolve under similar selection in D. melanogaster and was closer to the expectations from the theory of K-selection. At that time, we suggested two possible reasons for the differences in the phenotypic correlates of greater competitive ability seen in the studies with D. melanogaster and the other two species. First, that D. ananassae and D. n. nasuta had a very different genetic architecture of traits affecting competitive ability compared to the long-term laboratory populations of D. melanogaster used in the earlier studies, either because the populations of the former two species were relatively recently wild-caught, or by virtue of being different species. Second, that the different evolutionary trajectories in D. ananassae and D. n. nasuta versus D. melanogaster were a reflection of differences in the manner in which larval crowding was imposed in the two sets of selection experiments. The D. melanogaster studies used a higher absolute density of eggs per unit volume of food, and a substantially larger total volume of food, than the studies on D. ananassae and D. n. nasuta. Here, we

  13. The novel ABC transporter ABCH1 is a potential target for RNAi-based insect pest control and resistance management.

    Science.gov (United States)

    Guo, Zhaojiang; Kang, Shi; Zhu, Xun; Xia, Jixing; Wu, Qingjun; Wang, Shaoli; Xie, Wen; Zhang, Youjun

    2015-09-03

    Insect pests cause serious crop damage and develop high-level resistance to chemical insecticides and Bacillus thuringiensis (Bt) insecticidal Cry toxins. A new promising approach for controlling them and overcoming this resistance is RNA interference (RNAi). The RNAi-based insect control strategy depends on the selection of suitable target genes. In this study, we cloned and characterized a novel ABC transporter gene PxABCH1 in diamondback moth, Plutella xylostella (L.). Phylogenetic analysis showed that PxABCH1 is closely related to ABCA and ABCG subfamily members. Spatial-temporal expression detection revealed that PxABCH1 was expressed in all tissues and developmental stages, and highest expressed in head and male adult. Midgut sequence variation and expression analyses of PxABCH1 in all the susceptible and Bt-resistant P. xylostella strains and the functional analysis by sublethal RNAi demonstrated that Cry1Ac resistance was independent of this gene. Silencing of PxABCH1 by a relatively high dose of dsRNA dramatically reduced its expression and resulted in larval and pupal lethal phenotypes in both susceptible and Cry1Ac-resistant P. xylostella strains. To our knowledge, this study provides the first insight into ABCH1 in lepidopterans and reveals it as an excellent target for RNAi-based insect pest control and resistance management.

  14. Larval development and settlement of a whale barnacle.

    Science.gov (United States)

    Nogata, Yasuyuki; Matsumura, Kiyotaka

    2006-03-22

    Larval development and settlement of whale barnacles have not previously been described, unlike intertidal barnacles. Indeed, the mechanisms of the association between barnacles and whales have not been studied. Here we describe the larval development and settlement of the whale barnacle, Coronula diadema, and possible involvement of a cue from the host in inducing larval settlement. Eight-cell stage embryos were collected from C. diadema on a stranded humpback whale, incubated in filtered seawater for 7 days, and nauplius larvae hatched out. When fed with Chaetoceros gracilis, the nauplii developed to stage VI, and finally metamorphosed to the cypris stage. The larval development looked similar to that of intertidal barnacles with planktotrophic larval stages. The cyprids did not settle in normal seawater, but did settle in polystyrene Petri dishes when incubated in seawater with a small piece of skin tissue from the host whale. This strongly suggests the involvement of a chemical cue from the host whale tissue to induce larval settlement.

  15. Evaluating sampling strategies for larval cisco (Coregonus artedi)

    Science.gov (United States)

    Myers, J.T.; Stockwell, J.D.; Yule, D.L.; Black, J.A.

    2008-01-01

    To improve our ability to assess larval cisco (Coregonus artedi) populations in Lake Superior, we conducted a study to compare several sampling strategies. First, we compared density estimates of larval cisco concurrently captured in surface waters with a 2 x 1-m paired neuston net and a 0.5-m (diameter) conical net. Density estimates obtained from the two gear types were not significantly different, suggesting that the conical net is a reasonable alternative to the more cumbersome and costly neuston net. Next, we assessed the effect of tow pattern (sinusoidal versus straight tows) to examine if propeller wash affected larval density. We found no effect of propeller wash on the catchability of larval cisco. Given the availability of global positioning systems, we recommend sampling larval cisco using straight tows to simplify protocols and facilitate straightforward measurements of volume filtered. Finally, we investigated potential trends in larval cisco density estimates by sampling four time periods during the light period of a day at individual sites. Our results indicate no significant trends in larval density estimates during the day. We conclude estimates of larval cisco density across space are not confounded by time at a daily timescale. Well-designed, cost effective surveys of larval cisco abundance will help to further our understanding of this important Great Lakes forage species.

  16. Adaptive locomotor behavior in larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2011-01-01

    In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish.

  17. ‘Peer pressure’ in larval Drosophila?

    OpenAIRE

    Thomas Niewalda; Ines Jeske; Birgit Michels; Bertram Gerber

    2014-01-01

    ABSTRACT Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on ‘peer pressure’, that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group ...

  18. Microhabitat influence on larval fish assemblages within ...

    Science.gov (United States)

    We examined larval and juvenile fish assemblage structure in relation to microhabitat variables within the St. Louis River estuary, a drowned river mouth of Lake Superior. Fish were sampled in vegetated beds throughout the estuary, across a gradient of vegetation types and densities (including disturbed, preserved and post-restoration sites). Canonical correspondence analysis, relating species abundances to environmental variables revealed that plant species richness, turbidity and aquatic plant cover were most influential in structuring assemblages. Results from this microhabitat analysis at this crucial life stage has potential to inform wetland restoration efforts within the St. Louis River and other Great Lake coastal wetlands. not applicable

  19. Larval morphology of Metaphycus flavus and its role in host attachment and larval cannibalism.

    Science.gov (United States)

    Tena, A; Kapranas, A; Walker, G P; Garcia-Marí, F; Luck, R F

    2011-06-01

    Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50-70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.

  20. Larval development of Evermannia zosterura (Perciformes: Gobiidae).

    Science.gov (United States)

    González-Navarro, Enrique; Saldierna-Martínez, Ricardo Javier; Aceves-Medina, Gerardo

    2014-06-01

    Gobiidae is the most specious fish family in the world with almost 2 000 species, however only 11% of them have been described for their larval stages. The entire life cycle information is essential to understand the biology and ecology of this important fish group. Previous studies on zooplankton samples from Ensenada de La Paz, México, have shown the presence of several Gobiidae larvae and juveniles which were identified as Evermania zosterura. The main objective of this work was to describe the larval stages of this species, widely distributed in the Eastern tropical Pacific. The development of E. zosterura larvae was described based on 66 specimens. A total of 53 specimens were used to describe morphometrics and pigmentation patterns, while 13 specimens were cleared and stained, to obtain meristic characteristics. Cleared specimens had 30 to 31 total vertebrae; dorsal-fin elements: IV; 1, 13-14, anal-fin elements: 1, 13-14, and most had pterygiophore formula 4-111100. The combination of these characteristics confirmed these specimens as E. zosterura. The pigment pattern is similar throughout ontogeny. Larvae are characterized by having three to five dendritic melanophores along the post-anal ventral margin, four to nine smaller melanophores along the ventral margin between the isthmus and anus, and one on the midpoint of the dorsal margin of the tail. There is one small pigment spot on the angle of the jaw, and other on the tip of lower lip. There is an elongated internal pigment under the notochord, between the head and gas bladder. Notochord flexion starts near 3.5mm BL and ends at 4.6mm BL; transformalion to the juvenile stage is at about 13.6mm BL. Our conclusion is that the most useful characters to distinguish this species early-larval stages from those of similar species in the area, are the number of myomeres, the large melanophores (approximately uniformly in size) on the post anal ventral margin, and the elongate internal pigment under the notochord

  1. Turbulence-enhanced prey encounter rates in larval fish : Effects of spatial scale, larval behaviour and size

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; MacKenzie, Brian

    1995-01-01

    Turbulent water motion has several effects on the feeding ecology of larval fish and other planktivorous predators. In this paper, we consider the appropriate spatial scales for estimating relative velocities between larval fish predators and their prey, and the effect that different choices...

  2. Sandeel ( Ammodytes marinus ) larval transport patterns in the North Sea from an individual-based hydrodynamic egg and larval model

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Jensen, Henrik; Mosegaard, Henrik

    2008-01-01

    is modelled by a stochastic, nonlinear degree-day model describing the extended hatch period. The larval growth model is parameterized by individually back-tracking the local physical environment of larval survivors from their catch location and catch time. Using a detailed map of sandeel habitats...

  3. Coastal pollution limits pelagic larval dispersal.

    Science.gov (United States)

    Puritz, Jonathan B; Toonen, Robert J

    2011-01-01

    The ecological impact of large coastal human populations on marine ecosystems remains relatively unknown. Here, we examine the population structure of Patiria miniata, the bat star, and correlate genetic distances with a model based on flow rates and proximity to P. miniata populations for the four major stormwater runoff and wastewater effluent sources of the Southern California Bight. We show that overall genetic connectivity is high (F(ST)~0.005); however, multivariate analyses show that genetic structure is highly correlated with anthropogenic inputs. The best models included both stormwater and wastewater variables and explained between 26.55 and 93.69% of the observed structure. Additionally, regressions between allelic richness and distance to sources show that populations near anthropogenic pollution have reduced genetic diversity. Our results indicate that anthropogenic runoff and effluent are acting as barriers to larval dispersal, effectively isolating a high gene flow species that is virtually free of direct human impact.

  4. Modelling larval movement data from individual bioassays.

    Science.gov (United States)

    McLellan, Chris R; Worton, Bruce J; Deasy, William; Birch, A Nicholas E

    2015-05-01

    We consider modelling the movements of larvae using individual bioassays in which data are collected at a high-frequency rate of five observations per second. The aim is to characterize the behaviour of the larvae when exposed to attractant and repellent compounds. Mixtures of diffusion processes, as well as Hidden Markov models, are proposed as models of larval movement. These models account for directed and localized movements, and successfully distinguish between the behaviour of larvae exposed to attractant and repellent compounds. A simulation study illustrates the advantage of using a Hidden Markov model rather than a simpler mixture model. Practical aspects of model estimation and inference are considered on extensive data collected in a study of novel approaches for the management of cabbage root fly.

  5. The Larval Stage of Echinococcus Granulosus

    Directory of Open Access Journals (Sweden)

    Mohsen Sokouti

    2015-01-01

    Full Text Available Throughout the life cycle of Echinococcus granulosus, eggs of the parasite cannot mature into adult worms without first passing through the larval stage. Regarding the fact that this stage cannot take place in the definitive host, the eggs must look for an intermediate host, such as humans which are considered accidental intermediate hosts, in order to undergo their vital metamorphosis. In the upper gastrointestinal tract of the intermediate host, including humans (but not that of definitive host, the outer chitinous shells of the hexacanth embryos become lysed, enabling the embryos to penetrate the mucosa of the duodenum and upper jejunum to enter mesentric venule and be carried in the portal stream to the liver. Theoretically, a few of the embryos can enter the lymphatics of the intestinal wall and bypassing the liver through the cisterna chyli (1-3. It is believed that the larger amount of deoxycholic acid in the bile of herbivores and humans conjugated principally with glycine is responsible for lysis of the larva‘s protective center cuticle. On the other hand bile salts of carnivores such as dog are relatively poor in deoxy cholic acid which is linked with urine and have no effect on the cuticle of the larvae, which remain in the bowel lumen and developing into adult worms. Thus unlike what is mostly believed, humans do not serve as definitive hosts for the parasite; yet they carry only the larval forms which later penetrate into the villi of small bowel and form hydatid cyst in any organ of body (4-6.

  6. Mosquito larval source management for controlling malaria.

    Science.gov (United States)

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2013-08-29

    Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). To evaluate the effectiveness of mosquito LSM for preventing malaria. We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software. We included 13 studies; four cluster-RCTs, eight controlled before

  7. Mosquito larval source management for controlling malaria

    Science.gov (United States)

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2015-01-01

    Background Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). Objectives To evaluate the effectiveness of mosquito LSM for preventing malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. Selection criteria We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. Data collection and analysis At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software

  8. The endoparasitoid, Cotesia vestalis, regulates host physiology by reprogramming the neuropeptide transcriptional network.

    Science.gov (United States)

    Shi, Min; Dong, Shuai; Li, Ming-tian; Yang, Yan-yan; Stanley, David; Chen, Xue-xin

    2015-02-02

    Endoparasitoids develop inside another insect by regulating host immunity and development via maternal factors injected into hosts during oviposition. Prior results have provided insights into parasitism-induced immunosuppression, including the neuropeptide accumulation in parasitized insects. Nonetheless, our understanding of neuropeptide influence on host development and behavior is not yet complete. We posed the hypothesis that parasitization alters expression of genes encoding pro-neuropeptides and used larvae of Plutella xylostella and its endoparasitoid, Cotesia vestalis to test our hypothesis. We prepared transcriptomes from the larval P. xylostella brain-CC-CA complex and identified transcripts encoding 19 neuropeptides. All corresponding cDNAs were confirmed by RACE. Our results demonstrate that parasitism significantly down-regulated, or delayed, expression of genes encoding pro-neuropeptides within 48 h post-parasitization. Changing expression of these genes may account for the previously reported decreased feeding behavior, reduced growth rates and aborted development in the host larvae. In effect, parasitization may operate at the molecular level within the CNS to create global changes in larval host biology. The significance of our finding is that, in addition to the known effects on immunity, parasitoids influence host pro-neuropeptide gene transcription. This finding reveals a new mechanism operating in host-parasitoid relationships to the advantage of the parasitoid.

  9. 不结球白菜优异种质对小菜蛾抗性的遗传分析%Inheritance of the Resistance of Elite Germplasm to Diamondback Moth(plutella xylostella L.)in Non-heading Chinese Cabbage

    Institute of Scientific and Technical Information of China (English)

    陆鹏; 李锡香; 吴青君; 邱杨; 徐宝云; 王海平; 宋江萍; 王少伟

    2011-01-01

    以不结球白菜抗小菜蛾材料508为母本(P1)、以感虫材料114为父本(P2)构建了包括P1、P2、F1、F2、BC1P1和BC1P2的6个世代群体,通过人工网室鏊定各世代群体的抗虫性,利用主基因+多基因混合遗传模型联合分析法分析了不结球白菜抗虫遗传规律.结果表明:在508×114组合中,感虫对抗虫表现部分显性,抗虫性遗传符合一对加性-显性主基因+加性-显性多基因遗传模型,在BC1P1、BC1P2和F2群体中的主基因遗传率分别为57.21%、25.87%和76.05%,为有效利用抗虫资源和挖掘抗虫基因奠定了基础.%Insect-resistant inbred line 508 of the non-heading Chinese cabbage( Brassica chinensis L. )as female parent and susceptible inbred line 114 as male parent were used to construct six generation populations of P1、P2 、F1 、BC1P1 、BC1 P2and F2. The resistances of all the populations to diamondback moth(DBM) were evaluated in net, and the inheritance of insect-resistance for six generations was analyzed by joint analysis method. The results showed that the insect-resistance was partly recessive in the combination of 508 × 114 and fitted to the D-1 genetic model which is one pair of major additive-dominant gene plus additive-dominant polygene's. The heritability of the major genes in BC 1 P1, BC1 P2 and F2 populations were 57.21% ,25.87 % and 76.05 % , respectively. The results will be helpful for us to effectively utilize the insect-resistant gene resources in insect-resistance breeding.

  10. Evolved differences in larval social behavior mediated by novel pheromones.

    Science.gov (United States)

    Mast, Joshua D; De Moraes, Consuelo M; Alborn, Hans T; Lavis, Luke D; Stern, David L

    2014-12-12

    Pheromones, chemical signals that convey social information, mediate many insect social behaviors, including navigation and aggregation. Several studies have suggested that behavior during the immature larval stages of Drosophila development is influenced by pheromones, but none of these compounds or the pheromone-receptor neurons that sense them have been identified. Here we report a larval pheromone-signaling pathway. We found that larvae produce two novel long-chain fatty acids that are attractive to other larvae. We identified a single larval chemosensory neuron that detects these molecules. Two members of the pickpocket family of DEG/ENaC channel subunits (ppk23 and ppk29) are required to respond to these pheromones. This pheromone system is evolving quickly, since the larval exudates of D. simulans, the sister species of D. melanogaster, are not attractive to other larvae. Our results define a new pheromone signaling system in Drosophila that shares characteristics with pheromone systems in a wide diversity of insects.

  11. Behavioral analysis of the escape response in larval zebrafish

    Science.gov (United States)

    Feng, Ruopei; Girdhar, Kiran; Chemla, Yann; Gruebele, Martin

    The behavior of larval zebrafish is of great interest because the limited number of locomotor neurons in larval zebrafish couples with its rich repertoire of movements as a vertebrate animal. Current research uses a priori-selected parameters to describe their swimming behavior while our lab has built a parameter-free model based on singular value decomposition analysis to characterize it. Our previous work has analyzed the free swimming of larval zebrafish and presented a different picture from the current classification of larval zebrafish locomotion. Now we are extending this work to the studies of their escape response to acoustic stimulus. Analysis has shown intrinsic difference in the locomotion between escape response and free swimming.

  12. Measurements and Counts for Larval and Juvenile Beryx Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Larval alfonsin (Beryx species) were collected in the vicinity of the Southeast Hancock Seamount. A three-net Tucker trawl (I m2 effective mouth opening and 0.333 mm...

  13. Anatomical and physiological evidence for electroreception in larval lampreys.

    Science.gov (United States)

    Ronan, M

    1988-05-10

    In larval lampreys, the superficial ophthalmic, buccal, and recurrent rami of the anterior lateral line nerve project to the dorsal nucleus of the ipsilateral medulla; the posterior lateral line nerve projects to the medial nucleus bilaterally. The recurrent ramus is the largest source of afferents to the dorsal nucleus. Extracellular recordings from recurrent afferents in the trunk lateral line nerve indicate larval lampreys are sensitive to weak, low-frequency electric fields. Cathodal (outside negative) fields are excitatory; anodal fields are inhibitory.

  14. Contributions for larval development optimization of Homarus gammarus

    Directory of Open Access Journals (Sweden)

    Pedro Tiago Fonseca Sá

    2014-06-01

    The seawater rising temperature resulted in a decrease of intermoult period in all larval development stages and at all tested temperatures, ranging from 4.77 (Z1 to 16.5 days (Z3 at 16°C, whereas at 23°C, ranged from 3:02 (Z1 and 9.75 days (Z3. The results obtained are an extremely useful guide for future optimization of protocols on larval development of H. gammarus.

  15. Basic Gravitational Reflexes in the Larval Frog

    Science.gov (United States)

    Cochran, Stephen L.

    1996-01-01

    This investigation was designed to determine how a primitive vertebrate, the bullfrog tadpole, is able to sense and process gravitational stimuli. Because of the phylogenetic similarities of the vestibular systems in all vertebrates, the understanding of the gravitational reflexes in this relatively simple vertebrate should elucidate a skeletal framework on a elementary level, upon which the more elaborate reflexes of higher vertebrates may be constructed. The purpose of this study was to understand how the nervous system of the larval amphibian processes gravitational information. This study involved predominantly electrophysiological investigations of the isolated, alert (forebrain removed) bullfrog tadpole head. The focus of these experiments is threefold: (1) to understand from whole extraocular nerve recordings the signals sent to the eye following static gravitational tilt of the head; (2) to localize neuronal centers responsible for generating these signals through reversible pharmacological ablation of these centers; and (3) to record intracellularly from neurons within these centers in order to determine the single neuron's role in the overall processing of the center. This study has provided information on the mechanisms by which a primitive vertebrate processes gravitational reflexes.

  16. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  17. Turbulence-enhanced prey encounter rates in larval fish : Effects of spatial scale, larval behaviour and size

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; MacKenzie, Brian

    1995-01-01

    Turbulent water motion has several effects on the feeding ecology of larval fish and other planktivorous predators. In this paper, we consider the appropriate spatial scales for estimating relative velocities between larval fish predators and their prey, and the effect that different choices...... is consistent with classical coagulation theory. We then demonstrate that differences in larval search strategy (pause- travel versus cruise search) and behaviour (e.g. reactive distance, swimming speed, pause duration) will lead to substantial differences in estimated encounter rates. In general, small larvae...... are more likely to benefit from turbulence-increased encounter than larger larvae. Overall ingestion rate probability (= probability of encounter x probability of successful pursuit) is likely to be highest at moderate-high levels of turbulence. In most larval fish habitats, turbulence levels appear to lie...

  18. Triterpene acids from apple peel inhibit lepidopteran larval midgut lipases and larval growth.

    Science.gov (United States)

    Christeller, John T; McGhie, Tony K; Poulton, Joanne; Markwick, Ngaire P

    2014-07-01

    Fruit extracts from apple, kiwifruit, feijoa, boysenberry, and blueberry were screened for the presence of lipase inhibitory compounds against lepidopteran larval midgut crude extracts. From 120 extracts, six showed significant inhibition with an extract from the peel of Malus × domestica cv. "Big Red" showing highest levels of inhibition. Because this sample was the only apple peel sample in the initial screen, a survey of peels from seven apple cultivars was undertaken and showed that, despite considerable variation, all had inhibitory activity. Successive solvent fractionation and LC-MS of cv. "Big Red" apple peel extract identified triterpene acids as the most important inhibitory compounds, of which ursolic acid and oleanolic acid were the major components and oxo- and hydroxyl-triterpene acids were minor components. When ursolic acid was incorporated into artificial diet and fed to Epiphyas postvittana Walker (Tortricidae: Lepidoptera) larvae at 0.16% w/v, a significant decrease in larval weight was observed after 21 days. This concentration of ursolic acid is less than half the concentration reported in the skin of some apple cultivars. © 2014 Wiley Periodicals, Inc.

  19. The influence of larval migration and dispersal depth on potential larval trajectories of a deep-sea bivalve

    Science.gov (United States)

    McVeigh, Doreen M.; Eggleston, David B.; Todd, Austin C.; Young, Craig M.; He, Ruoying

    2017-09-01

    Many fundamental questions in marine ecology require an understanding of larval dispersal and connectivity, yet direct observations of larval trajectories are difficult or impossible to obtain. Although biophysical models provide an alternative approach, in the deep sea, essential biological parameters for these models have seldom been measured empirically. In this study, we used a biophysical model to explore the role of behaviorally mediated migration from two methane seep sites in the Gulf of Mexico on potential larval dispersal patterns and population connectivity of the deep-sea mussel "Bathymodiolus" childressi, a species for which some biological information is available. Three possible larval dispersal strategies were evaluated for larvae with a Planktonic Larval Duration (PLD) of 395 days: (1) demersal drift, (2) dispersal near the surface early in larval life followed by an extended demersal period before settlement, and (3) dispersal near the surface until just before settlement. Upward swimming speeds varied in the model based on the best data available. Average dispersal distances for simulated larvae varied between 16 km and 1488 km. Dispersal in the upper water column resulted in the greatest dispersal distance (1173 km ± 2.00), followed by mixed dispersal depth (921 km ± 2.00). Larvae originating in the Gulf of Mexico can potentially seed most known seep metapopulations on the Atlantic continental margin, whereas larvae drifting demersally cannot (237 km ± 1.43). Depth of dispersal is therefore shown to be a critical parameter for models of deep-sea connectivity.

  20. Using Linear Agarose Channels to Study Drosophila Larval Crawling Behavior.

    Science.gov (United States)

    Sun, Xiao; Heckscher, Ellie S

    2016-11-26

    Drosophila larval crawling is emerging as a powerful model to study neural control of sensorimotor behavior. However, larval crawling behavior on flat open surfaces is complex, including: pausing, turning, and meandering. This complexity in the repertoire of movement hinders detailed analysis of the events occurring during a single crawl stride cycle. To overcome this obstacle, linear agarose channels were made that constrain larval behavior to straight, sustained, rhythmic crawling. In principle, because agarose channels and the Drosophila larval body are both optically clear, the movement of larval structures labeled by genetically-encoded fluorescent probes can be monitored in intact, freely-moving larvae. In the past, larvae were placed in linear channels and crawling at the level of whole organism, segment, and muscle were analyzed(1). In the future, larvae crawling in channels can be used for calcium imaging to monitor neuronal activity. Moreover, these methods can be used with larvae of any genotype and with any researcher-designed channel. Thus the protocol presented below is widely applicable for studies using the Drosophila larva as a model to understand motor control.

  1. Adaptation to divergent larval diets in the medfly, Ceratitis capitata.

    Science.gov (United States)

    Leftwich, Philip T; Nash, William J; Friend, Lucy A; Chapman, Tracey

    2017-02-01

    Variation in diet can influence the timing of major life-history events and can drive population diversification and ultimately speciation. Proximate responses of life histories to diet have been well studied. However, there are scant experimental data on how organisms adapt to divergent diets over the longer term. We focused on this omission by testing the responses of a global pest, the Mediterranean fruitfly, to divergent selection on larval diets of different nutritional profiles. Tests conducted before and after 30 generations of nutritional selection revealed a complex interplay between the effects of novel larval dietary conditions on both plastic and evolved responses. There were proximate-only responses to the larval diet in adult male courtship and the frequency of copulation. Males on higher calorie larval diets consistently engaged in more bouts of energetic courtship. In contrast, following selection, larval development time, and egg to adult survival showed evidence of evolved divergence between diet regimes. Adult body size showed evidence for adaptation, with flies being significantly heavier when reared on their "own" diet. The results show the multifaceted responses of individuals to dietary selection and are important in understanding the extreme generalism exhibited by the medfly.

  2. Proteomic Analysis of Larval Midgut from the Silkworm (Bombyx mori

    Directory of Open Access Journals (Sweden)

    Sai Zhang

    2011-01-01

    Full Text Available The midgut is the major organ for food digestion, nutrient absorption and also a barrier for foreign substance. The 5th-instar larval stage of silkworm is very important for larval growth, development, and silk production. In the present study, we used 2-DE and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS to analyze the midgut proteins from the 5th-instar larvae as well as the midgut proteins under starvation condition. A total of 96 proteins were identified in this study; and among them, 69 proteins were observed in midgut for the first time. We also found that the silkworm larval midgut responded to starvation by producing a 10 kDa heat shock protein and a diapause hormone precursor.

  3. [Larval stages of Ascaris lumbricoides: hyaluronan-binding capacity].

    Science.gov (United States)

    Ponce-León, Patricia; Foresto, Patricia; Valverde, Juana

    2009-03-01

    Hyaluronic acid has important functions in inflammatory and tissue reparation processes. Owing to the varied strategies of the parasites to evade the host's immune response, as well as the multiple functions and physiological importance of hyaluronic acid, the aim was to study the hyaluronan binding capacity by Ascaris lumbricoides larval stages. Larval concentrates were prepared by hatching A. lumbricoides eggs. The larvae were collected by the Baermann method. The test of serum soluble CD44 detection by Agregation Inhibition was modified. All the larval concentrates presented hyaluronan binding capacity. The obtained results allow to suppose the existence of an hyaluronic acid specific receptor in A. lumbricoides. This receptor eventually might compete with the usual receptors of the host. The parasite might use this mechanism to evade the immune response.

  4. Oestrus ovis larval myiasis among goats in northern Jordan.

    Science.gov (United States)

    Abo-Shehada, Mahmoud N; Batainah, Tharwat; Abuharfeil, Nizar; Torgerson, P R

    2003-05-30

    From December 1998 to December 1999, heads of 520 local goats slaughtered at the Irbid, Ramtha and Howarra Abattoirs (northern Jordan) were examined for the three larval instars (L(1)-L(3)) of Oestrus ovis. Of 520 heads, 126 (24%) were infested with O. ovis larvae. All three larval instars were observed in both sexes; all age groups were infested in each month of the year. The mean age of the goats sampled was 1.5 years. The numbers of parasites infesting hosts showed a significant (P<0.05) correlation with sheep age (r(sp)=0.31-0.42) for all three larval instars. The numbers of larvae in each host followed an overdispersed distribution, which fit a negative-binomial model (but not a Poisson distribution). There were more parasites recorded in the presence of purulent discharge or laryngitis, fewer in the presence of catarrhal discharge and no association with pharyngitis sinusitis, or rhinitis.

  5. Characterization of anopheline (Diptera: Culicidae) larval habitats in Nouakchott, Mauritania.

    Science.gov (United States)

    Salem, O Ahmedou Salem Mohamed; Khadijetou, M Lekweiry; Moina, M Hasni; Lassana, Konate; Sébastien, Briolant; Ousmane, Faye; Ali, O Mohamed Salem Boukhary

    2013-12-01

    Despite the increasing number of reported autochthonous malaria cases in Nouakchott and the identification of Anopheles arabiensis as the major malaria vector in this Saharan city, anopheline larval habitats have never been identified so far. The objective of this study was to identify and characterize anopheline larval habitats in Nouakchott. During September and October 2012, samples from pools of rainwater, water discharged from standpipes and household drinking water tanks in the districts of Dar Naim, Teyarett and Arafat were analyzed for the presence/absence of anopheline larvae and physicochemical characterization of breeding habitats. Of the 51 prospected water bodies, eight consisting of seven water discharged from standpipes and one household drinking water tank were productive for Anopheles sp. All emerged anopheline mosquitoes from the positive dipping were morphologically identified as members of the An. gambiae complex. Multivariate regression analyses showed that a salinity up to 0.1 g/l and a shaded situation were respectively protective factors against high larval density in breeding sites (adjusted odds ratio = 0.62, 95% CI [0.44-0.87], p = 0.0052 and adjusted odds ratio = 0.56, 95% CI [0.44-0.71, p <0.0001] and a pH up to 7.61 was a risk factor for high larval density in breeding sites (adjusted odds ratio = 1.56, 95% CI [1.25-1.95], p = 0.0001). The study demonstrated in Nouakchott that despite an arid and dry climate, human practices have contributed to the establishment of favourable environmental conditions for the development of anopheline mosquitoes and, therefore, maintaining malaria transmission in this Saharan city. The core malaria vector control intervention as the use of long-lasting insecicidal nets (LLINs) could be complemented in Nouakchott by larval source control. In this area, appropriate larval control measures may be recommended in line with an integrated vector management (IVM) approach.

  6. Characterization of anopheline (Diptera: Culicidae larval habitats in Nouakchott, Mauritania

    Directory of Open Access Journals (Sweden)

    O. Ahmedou Salem Mohamed Salem

    2013-12-01

    Full Text Available Background & objectives: Despite the increasing number of reported autochthonous malaria cases in Nouakchott and the identification of Anopheles arabiensis as the major malaria vector in this Saharan city, anopheline larval habitats have never been identified so far. The objective of this study was to identify and characterize anopheline larval habitats in Nouakchott. Methods: During September and October 2012, samples from pools of rainwater, water discharged from standpipes and household drinking water tanks in the districts of Dar Naim, Teyarett and Arafat were analyzed for the presence/absence of anopheline larvae and physicochemical characterization of breeding habitats. Results: Of the 51 prospected water bodies, eight consisting of seven water discharged from standpipes and one household drinking water tank were productive for Anopheles sp. All emerged anopheline mosquitoes from the positive dipping were morphologically identified as members of the An. gambiae complex. Multivariate regression analyses showed that a salinity up to 0.1 g/l and a shaded situation were respectively protective factors against high larval density in breeding sites (adjusted odds ratio = 0.62, 95% CI [0.44-0.87], p = 0.0052 and adjusted odds ratio = 0.56, 95% CI [0.44-0.71, p <0.0001] and a pH up to 7.61 was a risk factor for high larval density in breeding sites (adjusted odds ratio = 1.56, 95% CI [1.25-1.95], p = 0.0001. Interpretation & conclusion: The study demonstrated in Nouakchott that despite an arid and dry climate, human practices have contributed to the establishment of favourable environmental conditions for the development of anopheline mosquitoes and, therefore, maintaining malaria transmission in this Saharan city. The core malaria vector control intervention as the use of long-lasting insecicidal nets (LLINs could be complemented in Nouakchott by larval source control. In this area, appropriate larval control measures may be recommended in line

  7. Effects of beach morphology and waves on onshore larval transport

    Science.gov (United States)

    Fujimura, A.; Reniers, A.; Paris, C. B.; Shanks, A.; MacMahan, J.; Morgan, S.

    2015-12-01

    Larvae of intertidal species grow offshore, and migrate back to the shore when they are ready to settle on their adult substrates. In order to reach the habitat, they must cross the surf zone, which is characterized as a semi-permeable barrier. This is accomplished through physical forcing (i.e., waves and current) as well as their own behavior. Two possible scenarios of onshore larval transport are proposed: Negatively buoyant larvae stay in the bottom boundary layer because of turbulence-dependent sinking behavior, and are carried toward the shore by streaming of the bottom boundary layer; positively buoyant larvae move to the shore during onshore wind events, and sink to the bottom once they encounter high turbulence (i.e., surf zone edge), where they are carried by the bottom current toward the shore (Fujimura et al. 2014). Our biophysical Lagrangian particle tracking model helps to explain how beach morphology and wave conditions affect larval distribution patterns and abundance. Model results and field observations show that larval abundance in the surf zone is higher at mildly sloped, rip-channeled beaches than at steep pocket beaches. Beach attributes are broken up to examine which and how beach configuration factors affect larval abundance. Modeling with alongshore uniform beaches with variable slopes reveal that larval populations in the surf zone are negatively correlated with beach steepness. Alongshore variability enhances onshore larval transport because of increased cross-shore water exchange by rip currents. Wave groups produce transient rip currents and enhance cross-shore exchange. Effects of other wave components, such as wave height and breaking wave rollers are also considered.

  8. Larval development of Brachiopod Coptothyris grayi (Davidson, 1852) (Brachiopoda, Rhynchonelliformea).

    Science.gov (United States)

    Kuzmina, T V; Temereva, E N; Malakhov, V V

    2016-11-01

    The larval development of the Brachiopod Coptothyris grayi (Davidson, 1852) from the Sea of Japan is described for the first time. Ciliated blastula proved to represent the first free-swimming stage. The blastopore is initially formed as a rounded hole stretching later along the anteroposterior axis. The larva is first divided into two lobes (the apical lobe and the trunk); the mantle lobe is formed later as two lateral folds. Two pairs of seta bundles appear in the late stage larvae. The apical larval lobe in brachiopods is supposed to match the pre-oral lobe and anterior part of the trunk with tentacles in phoronids.

  9. Aceitabilidade da terapia larval no tratamento de feridas

    OpenAIRE

    Franco,Letícia Cunha; Franco, Washington Cunha; Barros, Sávio Bertone Lopes; Araújo, Caroline Marinho; Rezende, Hanstter Halisson Alves

    2016-01-01

    Conhecer a opinião de pessoas hospitalizadas acerca da terapia larval como opção terapêutica. Estudo do tipo transversal e descritivo, realizado no setor de clínica médica e cirúrgica de um hospital de ensino, por meio de entrevista. Participaram da pesquisa 105 pessoas, dentre essas, 6 souberam dizer o que é uma bioterapia, 95 afirmaram que utilizariam a terapia larval, 32 se sentiam motivadas em aderir o tratamento devido à possibilidade de diminuir seus níveis de dor e 73 referiram medo em...

  10. The neural basis of visual behaviors in the larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2009-12-01

    We review visually guided behaviors in larval zebrafish and summarise what is known about the neural processing that results in these behaviors, paying particular attention to the progress made in the last 2 years. Using the examples of the optokinetic reflex, the optomotor response, prey tracking and the visual startle response, we illustrate how the larval zebrafish presents us with a very promising model vertebrate system that allows neurocientists to integrate functional and behavioral studies and from which we can expect illuminating insights in the near future.

  11. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    NARCIS (Netherlands)

    Bukhari, S.T.; Middelman, A.; Koenraadt, C.J.M.; Takken, W.; Knols, B.G.J.

    2010-01-01

    Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (species

  12. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    NARCIS (Netherlands)

    Bukhari, T.; Middelman, A.; Koenraadt, C.J.M.; Takken, W.; Knols, B.G.J.

    2010-01-01

    Background: Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (specie

  13. Different transcript patterns in response to specialist and generalist herbivores in the wild Arabidopsis relative Boechera divaricarpa.

    Directory of Open Access Journals (Sweden)

    Heiko Vogel

    Full Text Available BACKGROUND: Plants defend themselves against herbivorous insects, utilizing both constitutive and inducible defenses. Induced defenses are controlled by several phytohormone-mediated signaling pathways. Here, we analyze transcriptional changes in the North American Arabidopsis relative Boechera divaricarpa in response to larval herbivory by the crucifer specialist lepidopteran Plutella xylostella (diamondback moth and by the generalist lepidopteran Trichoplusia ni (cabbage semilooper, and compare them to wounding and exogenous phytohormone application. METHODOLOGY/PRINCIPAL FINDINGS: We use a custom macroarray constructed from B. divaricarpa herbivory-regulated cDNAs identified by suppression subtractive hybridization and from known stress-responsive A. thaliana genes for transcript profiling after insect herbivory, wounding and in response to jasmonate, salicylate and ethylene. In addition, we introduce path analysis as a novel approach to analyze transcript profiles. Path analyses reveal that transcriptional responses to the crucifer specialist P. xylostella are primarily determined by direct effects of the ethylene and salicylate pathways, whereas responses to the generalist T. ni are influenced by the ethylene and jasmonate pathways. Wound-induced transcriptional changes are influenced by all three pathways, with jasmonate having the strongest effect. CONCLUSIONS/SIGNIFICANCE: Our results show that insect herbivory is distinct from simple mechanical plant damage, and that different lepidopteran herbivores elicit different transcriptional responses.

  14. Biological studies on the snail intermediate hosts of schistosomiasis with a special emphasis on using larval echinostomes as biocontrol agent against larval schistosomes and snails.

    Science.gov (United States)

    Rashed, A A

    2002-12-01

    The present investigation deals with the infectivity of the two snail intermediate hosts of schistosomiasis, Biomphalaria alexandrina and Bulinus truncatus collected from nine drains in Sharkia Governorate, Egypt. The rate of infection among the snails was general low being 0% in many drains. Regarding B. alexandrina, the rate of infection ranged from 4-16%, and in B. truncatus ranged from 4-8%. Infection with larval echinostomes was dominant over larval schistosomes in the two snail vectors. The distribution of larval schistosomes was restricted to the hepatopancreas of the two snail vectors, while larval echinostomes were distributed in head, foot, kidney, haemocoelic cavity, hepatopancreas...etc. The predation of larval schistosomes by larval echinostomes and the severe histopathological effects induced by larval ecbinostomes strongly enhances using them as biocontrol agent. The physico-chemical parameters and pollution condition in the drains seem to have no effect on the process of snails infectivity. It is concluded that larval echinostomes can resist the polluting conditions in the drain. The two snail vectors exhibit very minimal or rare host response against larval echinostomes. Probably, the toxicants and pollutants in the drain may act as stressor that makes the snails much more susceptible to infection by larval trematodes.

  15. Efficiency of selection methods for increased ratio of pupal-larval to adult-larval weight gains in Tribolium.

    Science.gov (United States)

    Campo, J L; Cobos, P

    1994-01-12

    Four lines of Tribolium castaneum were selected in each of three replicates for increased ratio of (pupal-larval) to (adult-larval) weight gains, using selection for increased (pupal-larval) weight gain (PL), selection for decreased (adult-larval) weight gain (AL), direct selection for the ratio (R) and linear selection index of larval, pupal and adult weights (I), respectively, for four generations. Linear index was calculated with economic weights of m(2) -m(3) , m(3) -m(1) and m(1) -m(2) , respectively, with m(1) , m(2) and m(3) being the means for larval, pupal and adult weights. Selection to increase the ratio is considered to be a method to maximize the mean response in (adult-larval) weight while controlling the response in (pupal-adult) weight, and as a form of antagonistic selection to increase the weight gain during a given age period relative to the gain at another age period. Larval, pupal and adult weights were measured at 14, 21 and 28 days after adult emergence, respectively. The selected proportion was 20 % in all lines. The response observed for the ratio differed significantly among lines (p maximizar la respuesta en (peso de adulto-peso de larva) controlando al tiempo la respuesta en (peso de pupa-peso de adulto), y es una forma de selección antagónica para aumentar la ganancia de peso durante un periodo de edad en relación con la ganancia en peso durante otro periodo. La proporción de selección due el 20 %. La respuesta observada en el cociente difería significativamente entre lineas (p < 0.01), teniendo las líneas I y AL las mayores respuestas. La línea R fue menos efectiva, mientras que la línea PL parecía inapropiada para mejorar el objetiyo de selección. Las respuestas observadas en el denominador y en el numerador fueron positivas en la línea PL, y negativas en las otras tres líneas. Los resultados para este cociente mayor que 1 se comparan con los de otros experimentos para cocientes menores que 1, en los que la selecci

  16. Shifty salamanders: transient trophic polymorphism and cannibalism within natural populations of larval ambystomatid salamanders

    OpenAIRE

    Jefferson, Dale M; Ferrari, Maud CO; Mathis, Alicia; Hobson, Keith A.; Eric R Britzke; Crane, Adam L; Blaustein, Andrew R.; Chivers, Douglas P.

    2014-01-01

    Introduction Many species of ambystomatid salamanders are dependent upon highly variable temporary wetlands for larval development. High larval densities may prompt the expression of a distinct head morphology that may facilitate cannibalism. However, few studies have characterized structural cannibalism within natural populations of larval salamanders. In this study we used two species of larval salamanders, long-toed (Ambystoma macrodactylum) and ringed salamanders (A. annulatum). Head morp...

  17. Integrated mosquito larval source management reduces larval numbers in two highland villages in western Kenya

    Directory of Open Access Journals (Sweden)

    Imbahale Susan S

    2012-05-01

    Full Text Available Abstract Background In western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures. Methods Larval source management (LSM of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil, habitat manipulation (by provision of shading from arrow root plant, application of Bacillus thuringiensis var israelensis (Bti and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats. Results The findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89 % and 91 % chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively. Conclusion Most of these interventions were applied in habitats

  18. Larval Myogenesis in the Articulate Brachiopod Argyrotheca cordata (Risso, 1826)

    DEFF Research Database (Denmark)

    Altenburger, Andreas; Wanninger, Andreas Wilhelm Georg

    2008-01-01

    and micromorphological data to this debate, we investigated muscle formation in larvae of the brooding articulate brachiopod Argyrotheca cordata using immunocytochemistry combined with confocal laser scanning microscopy. Full grown larvae are three-lobed and show two pairs of bristle bundles. During larval development...

  19. Environmental factors limiting fertilisation and larval success in corals

    Science.gov (United States)

    Woods, Rachael M.; Baird, Andrew H.; Mizerek, Toni L.; Madin, Joshua S.

    2016-12-01

    Events in the early life history of reef-building corals, including fertilisation and larval survival, are susceptible to changes in the chemical and physical properties of sea water. Quantifying how changes in water quality affect these events is therefore important for understanding and predicting population establishment in novel and changing environments. A review of the literature identified that levels of salinity, temperature, pH, suspended sediment, nutrients and heavy metals affect coral early life-history stages to various degrees. In this study, we combined published experimental data to determine the relative importance of sea water properties for coral fertilisation success and larval survivorship. Of the water properties manipulated in experiments, fertilisation success was most sensitive to suspended sediment, copper, salinity, phosphate and ammonium. Larval survivorship was sensitive to copper, lead and salinity. A combined model was developed that estimated the joint probability of both fertilisation and larval survivorship in sea water with different chemical and physical properties. We demonstrated the combined model using water samples from Sydney and Lizard Island in Australia to estimate the likelihood of larvae surviving through both stages of development to settlement competency. Our combined model could be used to recommend targets for water quality in coastal waterways as well as to predict the potential for species to expand their geographical ranges in response to climate change.

  20. The role of individual variation in marine larval dispersal

    Directory of Open Access Journals (Sweden)

    Gerrit Berend Nanninga

    2014-12-01

    Full Text Available The exchange of individuals among patchy habitats plays a central role in spatial ecology and metapopulation dynamics. Dispersal (e.g. short vs. long is frequently observed to vary non-randomly within populations, indicating that variability among individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape heterogeneity (the context with phenotypic variability among individuals (the condition. While this hypothesis is widely accepted terrestrial theory, it remains questionable to what extent the concept of adaptive dispersal strategies may apply to marine larval dispersal, a process that is largely determined by stochastic forces. Yet, larvae of many taxa exhibit strong navigational capabilities and there is mounting evidence of widespread intra-specific variability in biological traits that are potentially correlated with dispersal potential. While so far there are few known examples of real larval dispersal polymorphisms, intra-specifically variable dispersal strategies may be common in marine systems. Whether adaptive or not, it is becoming apparent that inter-individual heterogeneity in morphology, behaviour, condition, and life history traits may have critical effects on population-level heterogeneity in dispersal. Here, we explore the eco-evolutionary causes and consequences of intrinsic and extrinsic variability on larval dispersal by synthesizing the existing literature and drawing conceptual parallels from terrestrial theory. We emphasize the potential importance of larval dispersal polymorphisms in marine population dynamics.

  1. Phenology of larval fish in the St. Louis River estuary

    Science.gov (United States)

    Little work has been done on the phenology of fish larvae in Great Lakes coastal wetlands. As part of an aquatic invasive species early detection study, we conducted larval fish surveys in the St. Louis River estuary (SLRE) in 2012 and 2013. Using multiple gears in a spatially ba...

  2. Basolateral Cl- channels in the larval bullfrog skin epithelium

    DEFF Research Database (Denmark)

    Hillyard, Stanley D.; Rios, K.; Larsen, Erik Hviid

    2002-01-01

    The addition of 150 U/ml nystatin to the mucosal surface of isolated skin from larval bullfrogs increases apical membrane permeability and allows a voltage clamp to be applied to the basolateral membrane. With identical Ringer's solutions bathing either side of the tissue the short-circuit current...

  3. Crustacean biodiversity as an important factor for mosquito larval control.

    Science.gov (United States)

    Kroeger, Iris; Duquesne, Sabine; Liess, Matthias

    2013-12-01

    Newly established ponds, which are highly dynamic systems with changing levels of biological interactions among species, are common larval mosquito habitats. We investigated the impact of crustacean abundance and taxa diversity on mosquito oviposition and larval development. The effects of the biological larvicide Bacillus thuringiensis israelensis (Bti) on mosquito larvae were monitored according to fluctuations in crustacean communities. Populations of the mosquito Culex pipiens colonized artificial ponds that contained crustacean communities at different time points of colonization by crustaceans: 1) 'no colonization' (no crustaceans), 2) 'simultaneous colonization' by crustaceans and mosquitoes, and 3) 'head-start colonization' by crustaceans (preceding colonization by mosquitoes). All types of ponds were treated with three concentrations of Bti (10, 100, or 1,000 µg/liter). Colonization of all ponds by Cx. pipiens (in terms of oviposition, larval abundance, and larval development) decreased significantly with increasing diversity of crustacean taxa. The total abundance of crustaceans had a minor effect on colonization by Cx. pipiens. The presence of crustaceans increased the sensitivity of Cx. pipiens larvae to Bti treatment by a factor of 10 and delayed the time of recolonization. This effect of Bti was relevant in the short term. In the long term, the presence of Cx. pipiens was determined by crustacean biodiversity. © 2013 The Society for Vector Ecology.

  4. Stretch-activated cation channel from larval bullfrog skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Willumsen, Niels J; Marrero, Mario B

    2010-01-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (-1 kPa to -4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed...... was markedly reduced with N-methyl-D-glucamide (NMDG)-Cl Ringer's solution in the pipette. Neither amiloride nor ATP, which are known to stimulate an apical cation channel in Ussing chamber preparations of larval frog skin, produced channel activation nor did these compounds affect the response to suction....... Stretch activation was not affected by varying the pipette concentrations of Ca(2+) between 0 mmol l(-1) and 4 mmol l(-1) or by varying pH between 6.8 and 8.0. However, conductance was reduced with 4 mmol l(-1) Ca(2+). Western blot analysis of membrane homogenates from larval bullfrog and larval toad skin...

  5. Development of environmental tools for anopheline larval control

    NARCIS (Netherlands)

    Imbahale, S.S.; Mweresa, C.K.; Takken, W.; Mukabana, W.R.

    2011-01-01

    Background: Malaria mosquitoes spend a considerable part of their life in the aquatic stage, rendering them vulnerable to interventions directed to aquatic habitats. Recent successes of mosquito larval control have been reported using environmental and biological tools. Here, we report the effects

  6. Fruit Fly Liquid Larval Diet Technology Transfer and Update

    Science.gov (United States)

    Since October 2006, USDA-ARS has been implementing a fruit fly liquid larval diet technology transfer, which has proceeded according to the following steps: (1) Recruitment of interested groups through request; (2) Establishment of the Material Transfer Agreement (MTA) with ARS; (3) Fruit fly liquid...

  7. Development of environmental tools for anopheline larval control

    NARCIS (Netherlands)

    Imbahale, S.S.; Mweresa, C.K.; Takken, W.; Mukabana, W.R.

    2011-01-01

    Background: Malaria mosquitoes spend a considerable part of their life in the aquatic stage, rendering them vulnerable to interventions directed to aquatic habitats. Recent successes of mosquito larval control have been reported using environmental and biological tools. Here, we report the effects o

  8. The role of individual variation in marine larval dispersal

    KAUST Repository

    Nanninga, Gerrit B.

    2014-12-08

    The exchange of individuals among patchy habitats plays a central role in spatial ecology and metapopulation dynamics. Dispersal is frequently observed to vary non-randomly within populations (e.g., short vs. long), indicating that variability among individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape heterogeneity (the context) with phenotypic variability among individuals (the condition). While this hypothesis is widely accepted in terrestrial theory, it remains questionable to what extent the concept of adaptive dispersal strategies may apply to marine larval dispersal, a process that is largely determined by stochastic forces. Yet, larvae of many taxa exhibit strong navigational capabilities and there is mounting evidence of widespread intra-specific variability in biological traits that are potentially correlated with dispersal potential. While so far there are few known examples of real larval dispersal polymorphisms, intra-specifically variable dispersal strategies may be common in marine systems. Whether adaptive or not, it is becoming apparent that inter-individual heterogeneity in morphology, behavior, condition, and life history traits may have critical effects on population-level heterogeneity in dispersal. Here, we explore the eco-evolutionary causes and consequences of intrinsic and extrinsic variability on larval dispersal by synthesizing the existing literature and drawing conceptual parallels from terrestrial theory. We emphasize the potential importance of larval dispersal polymorphisms in marine population dynamics.

  9. A staging system for larval cod (Gadus morhua L.)

    OpenAIRE

    1986-01-01

    A staging system of larval cod is described. The system is based on the resorption of the yolk mass and the cell layers surrounding it combined with eye, mouth and gut development. A determination key is given. Each stage is described in detail.

  10. Vibrio anguillarum and larval mortality in a California coastal shellfish hatchery.

    Science.gov (United States)

    DiSalvo, L H; Blecka, J; Zebal, R

    1978-01-01

    Vibrio anguillarum was isolated as a pathogen in the commercial culture of oyster spat at Pigeon Point, Calif. A water-soluble, heat-stable exotoxin extracted from cultures of the vibrio inhibited larval swimming and contributed to larval mortality. Although the vibrio was insensitive to penicillin in standard plate testing, this antibiotic proved useful in preventing mass larval mortalities in the hatchery.

  11. File list: InP.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.05.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.05.AllAg.Larval_brain.bed ...

  12. File list: His.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.20.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.20.AllAg.Larval_brain.bed ...

  13. File list: ALL.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.10.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426943,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.10.AllAg.Larval_brain.bed ...

  14. File list: His.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.05.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426945,SRX1426943... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.05.AllAg.Larval_brain.bed ...

  15. Foraging behavior of larval cod ( Gadus morhua ) influenced by prey density and hunger

    DEFF Research Database (Denmark)

    Munk, Peter

    1995-01-01

    Fish larvae meet diverse environmental conditions at sea, and larval growth and chance of survival depend on a flexible response to environmental variability. The present study focuses on the flexibility of the foraging behaviour of larval cod in a series of laboratory experiments on larval search...

  16. File list: ALL.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426946,SRX1426943 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.Larval_brain.bed ...

  17. File list: His.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.50.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.50.AllAg.Larval_brain.bed ...

  18. File list: ALL.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.Larval_brain.bed ...

  19. File list: ALL.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.Larval_brain.bed ...

  20. File list: His.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426945,SRX1426943... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.10.AllAg.Larval_brain.bed ...

  1. File list: InP.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.10.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.10.AllAg.Larval_brain.bed ...

  2. File list: InP.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.50.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.50.AllAg.Larval_brain.bed ...

  3. File list: InP.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.20.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.20.AllAg.Larval_brain.bed ...

  4. Parasitismo de traça-das-crucíferas por Oomyzus sokolowskii Parasitism of diamondback moth by Oomyzus sokolowskii

    Directory of Open Access Journals (Sweden)

    Christian Sherley Araújo da Silva-Torres

    2010-07-01

    Full Text Available O objetivo deste trabalho foi avaliar a capacidade de parasitismo do parasitoide larval-pupal Oomyzus sokolowskii, submetido a diferentes densidades do hospedeiro traça-das-crucíferas (Plutella xylostella, em laboratório, casa telada e campo. Em laboratório e campo, O. sokolowskii foi exposto às densidades de 2, 4, 8 e 16 lagartas. Em laboratório, empregaram-se recipientes de 300 mL e, em campo, plantas de couve foram confinadas em gaiolas de organza (30x50 cm. Em casa telada, foram utilizadas microparcelas compostas por seis plantas de repolho infestadas com 25, 50, 85 ou 100 lagartas. O número de lagartas parasitadas aumentou de acordo com a densidade do hospedeiro e variou de 1,7 a 10,4, em laboratório, e de 0,61 a 7,0, em campo. Em casa telada, a maior taxa de parasitismo foi observada nas microparcelas com densidades mais elevadas do hospedeiro. O tempo de exposição aos parasitoides proporcionou maior taxa de parasitismo após 72 horas (24 horas, 52,4% e 72 horas, 80,7% independentemente da densidade. Oomyzus sokolowskii responde positivamente ao incremento na densidade de P. xylostella, embora a taxa de parasitismo permaneça constante independentemente da disponibilidade do hospedeiro.The objective of this work was to evaluate the parasitism capacity of the larval-pupal parasitoid Oomyzus sokolowskii submitted to different densities of the host diamondback moth, Plutella xylostella, in the laboratory, greenhouse and field. In the laboratory and in the field, O. sokolowskii was exposed to densities of 2, 4, 8 or 16 larvae. In the laboratory, 300 mL recipient were used, and in the field kale plants were placed in cages (30x50 cm. In the greenhouse, microparcels consisted of six cabbage plants each infested with 25, 50, 85 or 100 larvae. The number of parasitized larvae increased with host density and varied from 1.7 to 10.4 (laboratory and from 0.61 to 7.0 (field. In the greenhouse, parasitism rate was higher in microparcels with

  5. Food selection in larval fruit flies: dynamics and effects on larval development

    Science.gov (United States)

    Schwarz, Sebastian; Durisko, Zachary; Dukas, Reuven

    2014-01-01

    Selecting food items and attaining a nutritionally balanced diet is an important challenge for all animals including humans. We aimed to establish fruit fly larvae ( Drosophila melanogaster) as a simple yet powerful model system for examining the mechanisms of specific hunger and diet selection. In two lab experiments with artificial diets, we found that larvae deprived of either sucrose or protein later selectively fed on a diet providing the missing nutrient. When allowed to freely move between two adjacent food patches, larvae surprisingly preferred to settle on one patch containing yeast and ignored the patch providing sucrose. Moreover, when allowed to move freely between three patches, which provided either yeast only, sucrose only or a balanced mixture of yeast and sucrose, the majority of larvae settled on the yeast-plus-sucrose patch and about one third chose to feed on the yeast only food. While protein (yeast) is essential for development, we also quantified larval success on diets with or without sucrose and show that larvae develop faster on diets containing sucrose. Our data suggest that fruit fly larvae can quickly assess major nutrients in food and seek a diet providing a missing nutrient. The larvae, however, probably prefer to quickly dig into a single food substrate for enhanced protection over achieving an optimal diet.

  6. Stretch-activated cation channel from larval bullfrog skin.

    Science.gov (United States)

    Hillyard, Stanley D; Willumsen, Niels J; Marrero, Mario B

    2010-05-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (-1 kPa to -4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed a variable pattern of opening and closing with continuing suction. Current-voltage plots demonstrated linear or inward rectification and single channel conductances of 44-56 pS with NaCl or KCl Ringer's solution as the pipette solution, and a reversal potential (-V(p)) of 20-40 mV. The conductance was markedly reduced with N-methyl-D-glucamide (NMDG)-Cl Ringer's solution in the pipette. Neither amiloride nor ATP, which are known to stimulate an apical cation channel in Ussing chamber preparations of larval frog skin, produced channel activation nor did these compounds affect the response to suction. Stretch activation was not affected by varying the pipette concentrations of Ca(2+) between 0 mmol l(-1) and 4 mmol l(-1) or by varying pH between 6.8 and 8.0. However, conductance was reduced with 4 mmol l(-1) Ca(2+). Western blot analysis of membrane homogenates from larval bullfrog and larval toad skin identified proteins that were immunoreactive with mammalian TRPC1 and TRPC5 (TRPC, canonical transient receptor potential channel) antibodies while homogenates of skin from newly metamorphosed bullfrogs were positive for TRPC1 and TRPC3/6/7 antibodies. The electrophysiological response of larval bullfrog skin resembles that of a stretch-activated cation channel characterized in Xenopus oocytes and proposed to be TRPC1. These results indicate this channel persists in all life stages of anurans and that TRP isoforms may be important for sensory functions of their skin.

  7. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi.

    Science.gov (United States)

    Vogels, Chantal B F; Bukhari, Tullu; Koenraadt, Constantianus J M

    2014-06-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible.

  8. 西双版纳棚栽辣木主要害虫及防治%Major Pests of Moringa oleifera in Greenhouse and Their Control in Xishuangbanna

    Institute of Scientific and Technical Information of China (English)

    刘昌芬; 杨焱; 龙继明

    2011-01-01

    介绍了西双版纳棚栽辣木存在的主要害虫:朱砂叶螨(Tetranychus cinnabarinus Boisduval)、美洲斑潜蝇(Liriomyza sativae Blanchard)、斜纹夜蛾(Prodenia litura Fabricius)和小菜蛾(Plutella xylostella L.)为害症状和防治。%There are several pests damaged Moringa oleifera tree of greenhouse,namely Tetranychus cinnabarinus Boisduval,Liriomyza ativae Blanchard,Prodenia litura Fabricius and Plutella xylostella L..

  9. Numerical simulations of barnacle larval dispersion coupled with field observations on larval abundance, settlement and recruitment in a tropical monsoon influenced coastal marine environment

    Science.gov (United States)

    Gaonkar, Chetan A.; Samiksha, S. V.; George, Grinson; Aboobacker, V. M.; Vethamony, P.; Anil, Arga Chandrashekar

    2012-06-01

    Larval abundance in an area depends on various factors which operate over different spatial and temporal scales. Identifying the factors responsible for variations in larval supply and abundance is important to understand the settlement and recruitment variability of their population in a particular area. In view of this, observations were carried out to monitor the larval abundance, settlement and recruitment of barnacles on a regular basis for a period of two years. The results were then compared with the numerical modelling studies carried out along the west coast of India. Field observations of larval abundance showed temporal variations. The least abundance of larvae was mostly observed during the monsoon season and the peak in abundance was mostly observed during the pre-monsoon season. Numerical simulations also showed a seasonal change in larval dispersion and retention patterns. During pre-monsoon season the larval movement was mostly found towards south and the larvae released from the northern release sites contributed to larval abundance within the estuaries, whereas during the monsoon season the larval movement was mostly found towards north and the larvae released from southern release sites contributed to larval abundance within the estuary. During post-monsoon season, the larval movement was found towards the north in the beginning of the season and is shifted towards the south at the end of the season, but the movement was mostly restricted near to the release sites. Larval supply from the adjacent rocky sites to the estuaries was higher during the pre-monsoon season and the retention of larvae released from different sites within the estuaries was found to be highest during the late post-monsoon and early pre-monsoon season. Maximum larval supply and retention during the pre-monsoon season coincided with maximum larval abundance, settlement and recruitment of barnacles observed in the field studies. These observations showed that the pattern of

  10. Insecticidal and Feeding Deterrent Effects of Fraxinellone from Dictamnus dasycarpus against Four Major Pests

    Directory of Open Access Journals (Sweden)

    Huixia Liu

    2013-03-01

    Full Text Available Fraxinellone, a well-known and significant naturally occurring compound isolated from Meliaceae and Rutaceae spp. has been widely used as a drug for the treatment of tumors. On the other hand, fraxinellone exhibited a variety of insecticidal activities including feeding-deterrent activity, inhibition of growth, and larvicidal activity. The present study focused on the antifeedant and larvicidal activities of fraxinellone against the larvae of Lepidoptera, including Mythimna separata, Agrotis ypsilon, Plutella xylostella, and one kind of sanitary pest, Culux pipiens pallens. Meanwhile, the ovicidal activities and the effects of fraxinellone on the larval development of M. separata were also observed. The LC50 values of fraxinellone against 3rd instar larvae of M. separata, 2nd instar larvae of P. xylostella and 4th instar larvae of C. pipiens pallens were 15.95/6.43/3.60 × 10−2 mg mL−1, and its AFC50 values against 5th instar larvae of M. separata, 2nd instar larvae of P. xylostella and 2nd instar larvae of A. ypsilon were 10.73/7.93/12.58 mg mL−1, respectively. Compared with the control group, fraxinellone obviously inhibited the pupation rate and the growth of M. separata. Once M. separata was treated with fraxinellone at concentrations of 5.0, 10.0, and 20.0 mg mL−1, respectively, the stages from the larvae to adulthood and the egg hatching duration were prolonged to 1/2/3, and 4/3/4 days, respectively. Additionally, fraxinellone strongly inhibited the development rate and the egg hatch proportion of M. separata.

  11. Inhibition of Haemonchus contortus larval development by fungal lectins.

    Science.gov (United States)

    Heim, Christian; Hertzberg, Hubertus; Butschi, Alex; Bleuler-Martinez, Silvia; Aebi, Markus; Deplazes, Peter; Künzler, Markus; Štefanić, Saša

    2015-08-19

    Lectins are carbohydrate-binding proteins that are involved in fundamental intra- and extracellular biological processes. They occur ubiquitously in nature and are especially abundant in plants and fungi. It has been well established that certain higher fungi produce lectins in their fruiting bodies and/or sclerotia as a part of their natural resistance against free-living fungivorous nematodes and other pests. Despite relatively high diversity of the glycan structures in nature, many of the glycans targeted by fungal lectins are conserved among organisms of the same taxon and sometimes even among different taxa. Such conservation of glycans between free-living and parasitic nematodes is providing us with a useful tool for discovery of novel chemotherapeutic and vaccine targets. In our study, a subset of fungal lectins emanating from toxicity screens on Caenorhabditis elegans was tested for their potential to inhibit larval development of Haemonchus contortus. The effect of Coprinopsis cinerea lectins - CCL2, CGL2, CGL3; Aleuria aurantia lectin - AAL; Marasmius oreades agglutinin - MOA; and Laccaria bicolor lectin - Lb-Tec2, on cultivated Haemonchus contortus larval stages was investigated using a larval development test (LDT). To validate the results of the toxicity assay and determine lectin binding capacity to the nematode digestive tract, biotinylated versions of lectins were fed to pre-infective larval stages of H. contortus and visualized by fluorescent microscopy. Lectin histochemistry on fixed adult worms was performed to investigate the presence and localisation of lectin binding sites in the disease-relevant developmental stage. Using an improved larval development test we found that four of the six tested lectins: AAL, CCL2, MOA and CGL2, exhibited a dose-dependent toxicity in LDT, as measured by the number of larvae developing to the L3 stage. In the case of AAL, CGL2 and MOA lectin, doses as low as 5 μg/ml caused >95 % inhibition of larval

  12. Learning the specific quality of taste reinforcement in larval Drosophila.

    Science.gov (United States)

    Schleyer, Michael; Miura, Daisuke; Tanimura, Teiichi; Gerber, Bertram

    2015-01-27

    The only property of reinforcement insects are commonly thought to learn about is its value. We show that larval Drosophila not only remember the value of reinforcement (How much?), but also its quality (What?). This is demonstrated both within the appetitive domain by using sugar vs amino acid as different reward qualities, and within the aversive domain by using bitter vs high-concentration salt as different qualities of punishment. From the available literature, such nuanced memories for the quality of reinforcement are unexpected and pose a challenge to present models of how insect memory is organized. Given that animals as simple as larval Drosophila, endowed with but 10,000 neurons, operate with both reinforcement value and quality, we suggest that both are fundamental aspects of mnemonic processing-in any brain.

  13. Effects of moisture content of food waste on residue separation, larval growth and larval survival in black soldier fly bioconversion.

    Science.gov (United States)

    Cheng, Jack Y K; Chiu, Sam L H; Lo, Irene M C

    2017-09-01

    In order to foster sustainable management of food waste, innovations in food waste valorization technologies are crucial. Black soldier fly (BSF) bioconversion is an emerging technology that can turn food waste into high-protein fish feed through the use of BSF larvae. The conventional method of BSF bioconversion is to feed BSF larvae with food waste directly without any moisture adjustment. However, it was reported that difficulty has been experienced in the separation of the residue (larval excreta and undigested material) from the insect biomass due to excessive moisture. In addition to the residue separation problem, the moisture content of the food waste may also affect the growth and survival aspects of BSF larvae. This study aims to determine the most suitable moisture content of food waste that can improve residue separation as well as evaluate the effects of the moisture content of food waste on larval growth and survival. In this study, pre-consumer and post-consumer food waste with different moisture content (70%, 75% and 80%) was fed to BSF larvae in a temperature-controlled rotary drum reactor. The results show that the residue can be effectively separated from the insect biomass by sieving using a 2.36mm sieve, for both types of food waste at 70% and 75% moisture content. However, sieving of the residue was not feasible for food waste at 80% moisture content. On the other hand, reduced moisture content of food waste was found to slow down larval growth. Hence, there is a trade-off between the sieving efficiency of the residue and the larval growth rate. Furthermore, the larval survival rate was not affected by the moisture content of food waste. A high larval survival rate of at least 95% was achieved using a temperature-controlled rotary drum reactor for all treatment groups. The study provides valuable insights for the waste management industry on understanding the effects of moisture content when employing BSF bioconversion for food waste recycling

  14. Fish larval transport in the coastal waters through ecological modelling

    Digital Repository Service at National Institute of Oceanography (India)

    George, G.

    ) numerically tracking the transport of larvae released from spawning sites based on hydrodynamics of the regions, and comparison with measurements (vi) interpreting the data sets generated by numerical simulation studies to infer the nursery areas and seasonal..., L. B. Crowder, J. A. Rice, and E. A. Marschall. Larval size and recruitment mechanisms in fishes: towards a conceptual framework. Canadian Journal of Fisheries and Aquatic Sciences, 45:1657–1670, 1988. Y. Miyake, S. Kimura, T. Kawamura, T. Horii, H...

  15. Rapid effects of marine reserves via larval dispersal.

    Directory of Open Access Journals (Sweden)

    Richard Cudney-Bueno

    Full Text Available Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs, with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

  16. Rapid effects of marine reserves via larval dispersal.

    Science.gov (United States)

    Cudney-Bueno, Richard; Lavín, Miguel F; Marinone, Silvio G; Raimondi, Peter T; Shaw, William W

    2009-01-01

    Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs), with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

  17. Managing Ammonia Emissions From Screwworm Larval Rearing Media.

    Science.gov (United States)

    Sagel, Agustin; Phillips, Pamela; Chaudhury, Muhammad; Skoda, Steven

    2016-02-01

    Mass production, sterilization, and release of screwworms (Cochliomyia hominivorax (Coquerel)) that were competitive in the field significantly contributed to the successful application of the sterile insect technique for eradication of screwworms from continental North America. Metabolic byproducts resulting from protein-rich diets required for larval screwworms lead to ammonia liberation, sometimes at high levels, within the mass rearing facility. Until recently a sodium polyacrylate gel bulking agent was used for the larval media and adsorbed much of the ammonia. A need to replace the gel with an environmentally "friendly" bulking agent, while not increasing ammonia levels in the rearing facility, led to a series of experiments with the objective of developing procedures to reduce ammonia emissions from the larval media bulked with cellulose fiber. Additives of ammonia-converting bacteria, potassium permanganate, and Yucca schidigera Roezl ex Otrgies powder extract, previously reported to reduce ammonia levels in organic environments, were evaluated. Ammonia-converting bacteria did not have a positive effect. Addition of Y. schidigera powder extract (∼1% of total volume), potassium permanganate (∼250 ppm), and a combination of these two additives (at these same concentrations) kept ammonia at equivalent levels as when larval media was bulked with gel. Potassium permanganate also had sufficient antimicrobial properties that the use of formaldehyde in the diet was not necessary. Further testing is needed, at a mass rearing level, before full implementation into the screwworm eradication program. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  18. Social coercion of larval development in an ant species

    Science.gov (United States)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  19. Development of environmental tools for anopheline larval control

    OpenAIRE

    Mweresa Collins K; Imbahale Susan S; Takken Willem; Mukabana Wolfgang R

    2011-01-01

    Abstract Background Malaria mosquitoes spend a considerable part of their life in the aquatic stage, rendering them vulnerable to interventions directed to aquatic habitats. Recent successes of mosquito larval control have been reported using environmental and biological tools. Here, we report the effects of shading by plants and biological control agents on the development and survival of anopheline and culicine mosquito larvae in man-made natural habitats in western Kenya. Trials consisted ...

  20. Larval connectivity in an effective network of marine protected areas.

    Directory of Open Access Journals (Sweden)

    Mark R Christie

    Full Text Available Acceptance of marine protected areas (MPAs as fishery and conservation tools has been hampered by lack of direct evidence that MPAs successfully seed unprotected areas with larvae of targeted species. For the first time, we present direct evidence of large-scale population connectivity within an existing and effective network of MPAs. A new parentage analysis identified four parent-offspring pairs from a large, exploited population of the coral-reef fish Zebrasoma flavescens in Hawai'i, revealing larval dispersal distances ranging from 15 to 184 km. In two cases, successful dispersal was from an MPA to unprotected sites. Given high adult abundances, the documentation of any parent-offspring pairs demonstrates that ecologically-relevant larval connectivity between reefs is substantial. All offspring settled at sites to the north of where they were spawned. Satellite altimetry and oceanographic models from relevant time periods indicated a cyclonic eddy that created prevailing northward currents between sites where parents and offspring were found. These findings empirically demonstrate the effectiveness of MPAs as useful conservation and management tools and further highlight the importance of coupling oceanographic, genetic, and ecological data to predict, validate and quantify larval connectivity among marine populations.

  1. A subset of interneurons required for Drosophila larval locomotion.

    Science.gov (United States)

    Yoshikawa, Shingo; Long, Hong; Thomas, John B

    2016-01-01

    Efforts to define the neural circuits generating locomotor behavior have produced an initial understanding of some of the components within the spinal cord, as well as a basic understanding of several invertebrate motor pattern generators. However, how these circuits are assembled during development is poorly understood. We are defining the neural circuit that generates larval locomotion in the genetically tractable fruit fly Drosophila melanogaster to study locomotor circuit development. Forward larval locomotion involves a stereotyped posterior-to-anterior segmental translocation of body wall muscle contraction and is generated by a relatively small number of identified muscles, motor and sensory neurons, plus an unknown number of the ~270 bilaterally-paired interneurons per segment of the 1st instar larva. To begin identifying the relevant interneurons, we have conditionally inactivated synaptic transmission of interneuron subsets and assayed for the effects on locomotion. From this screen we have identified a subset of 25 interneurons per hemisegment, called the lateral locomotor neurons (LLNs), that are required for locomotion. Both inactivation and constitutive activation of the LLNs disrupt locomotion, indicating that patterned output of the LLNs is required. By expressing a calcium indicator in the LLNs, we found that they display a posterior-to-anterior wave of activity within the CNS corresponding to the segmental translocation of the muscle contraction wave. Identification of the LLNs represents the first step toward elucidating the circuit generating larval locomotion.

  2. Embryogenesis, hatching and larval development of Artemia during orbital spaceflight

    Science.gov (United States)

    Spooner, B. S.; Debell, L.; Armbrust, L.; Guikema, J. A.; Metcalf, J.; Paulsen, A.

    1994-01-01

    Developmental biology studies, using gastrula-arrested cysts of the brine shrimp Artemia franciscana, were conducted during two flights of the space shuttle Atlantis (missions STS-37 and STS-43) in 1991. Dehydrated cysts were activated, on orbit, by addition of salt water to the cysts, and then development was terminated by the addition of fixative. Development took place in 5 ml syringes, connected by tubing to activation syringes, containing salt water, and termination syringes, containing fixative. Comparison of space results with simultaneous ground control experiments showed that equivalent percentages of naupliar larvae hatched in the syringes (40%). Thus, reactivation of development, completion of embryogenesis, emergence and hatching took place, during spaceflight, without recognizable alteration in numbers of larvae produced. Post-hatching larval development was studied in experiments where development was terminated, by introduction of fixative, 2 days, 4 days, and 8 days after reinitiation of development. During spaceflight, successive larval instars or stages, interrupted by molts, occurred, generating brine shrimp at appropriate larval instars. Naupliar larvae possessed the single naupliar eye, and development of the lateral pair of adult eyes also took place in space. Transmission electron microscopy revealed extensive differentiation, including skeletal muscle and gut endoderm, as well as the eye tissues. These studies demonstrate the potential value of Artemia for developmental biology studies during spa ceflight, and show that extensive degrees of development can take place in this microgravity environment.

  3. Oceanography promotes self-recruitment in a planktonic larval disperser

    Science.gov (United States)

    Teske, Peter R.; Sandoval-Castillo, Jonathan; van Sebille, Erik; Waters, Jonathan; Beheregaray, Luciano B.

    2016-01-01

    The application of high-resolution genetic data has revealed that oceanographic connectivity in marine species with planktonic larvae can be surprisingly limited, even in the absence of major barriers to dispersal. Australia’s southern coast represents a particularly interesting system for studying planktonic larval dispersal, as the hydrodynamic regime of the wide continental shelf has potential to facilitate onshore retention of larvae. We used a seascape genetics approach (the joint analysis of genetic data and oceanographic connectivity simulations) to assess population genetic structure and self-recruitment in a broadcast-spawning marine gastropod that exists as a single meta-population throughout its temperate Australian range. Levels of self-recruitment were surprisingly high, and oceanographic connectivity simulations indicated that this was a result of low-velocity nearshore currents promoting the retention of planktonic larvae in the vicinity of natal sites. Even though the model applied here is comparatively simple and assumes that the dispersal of planktonic larvae is passive, we find that oceanography alone is sufficient to explain the high levels of genetic structure and self-recruitment. Our study contributes to growing evidence that sophisticated larval behaviour is not a prerequisite for larval retention in the nearshore region in planktonic-developing species. PMID:27687507

  4. Larval RNA interference in the red flour beetle, Tribolium castaneum.

    Science.gov (United States)

    Linz, David M; Clark-Hachtel, Courtney M; Borràs-Castells, Ferran; Tomoyasu, Yoshinori

    2014-10-13

    The red flour beetle, Tribolium castaneum, offers a repertoire of experimental tools for genetic and developmental studies, including a fully annotated genome sequence, transposon-based transgenesis, and effective RNA interference (RNAi). Among these advantages, RNAi-based gene knockdown techniques are at the core of Tribolium research. T. castaneum show a robust systemic RNAi response, making it possible to perform RNAi at any life stage by simply injecting double-stranded RNA (dsRNA) into the beetle's body cavity. In this report, we provide an overview of our larval RNAi technique in T. castaneum. The protocol includes (i) isolation of the proper stage of T. castaneum larvae for injection, (ii) preparation for the injection setting, and (iii) dsRNA injection. Larval RNAi is a simple, but powerful technique that provides us with quick access to loss-of-function phenotypes, including multiple gene knockdown phenotypes as well as a series of hypomorphic phenotypes. Since virtually all T. castaneum tissues are susceptible to extracellular dsRNA, the larval RNAi technique allows researchers to study a wide variety of tissues in diverse contexts, including the genetic basis of organismal responses to the outside environment. In addition, the simplicity of this technique stimulates more student involvement in research, making T. castaneum an ideal genetic system for use in a classroom setting.

  5. Oceanography promotes self-recruitment in a planktonic larval disperser.

    Science.gov (United States)

    Teske, Peter R; Sandoval-Castillo, Jonathan; van Sebille, Erik; Waters, Jonathan; Beheregaray, Luciano B

    2016-09-30

    The application of high-resolution genetic data has revealed that oceanographic connectivity in marine species with planktonic larvae can be surprisingly limited, even in the absence of major barriers to dispersal. Australia's southern coast represents a particularly interesting system for studying planktonic larval dispersal, as the hydrodynamic regime of the wide continental shelf has potential to facilitate onshore retention of larvae. We used a seascape genetics approach (the joint analysis of genetic data and oceanographic connectivity simulations) to assess population genetic structure and self-recruitment in a broadcast-spawning marine gastropod that exists as a single meta-population throughout its temperate Australian range. Levels of self-recruitment were surprisingly high, and oceanographic connectivity simulations indicated that this was a result of low-velocity nearshore currents promoting the retention of planktonic larvae in the vicinity of natal sites. Even though the model applied here is comparatively simple and assumes that the dispersal of planktonic larvae is passive, we find that oceanography alone is sufficient to explain the high levels of genetic structure and self-recruitment. Our study contributes to growing evidence that sophisticated larval behaviour is not a prerequisite for larval retention in the nearshore region in planktonic-developing species.

  6. Characterisation of Culex quinquefasciatus (Diptera: Culicidae larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Marta Grech

    2013-09-01

    Full Text Available The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase.

  7. Isolation and culture of larval cells from C. elegans.

    Directory of Open Access Journals (Sweden)

    Sihui Zhang

    Full Text Available Cell culture is an essential tool to study cell function. In C. elegans the ability to isolate and culture cells has been limited to embryonically derived cells. However, cells or blastomeres isolated from mixed stage embryos terminally differentiate within 24 hours of culture, thus precluding post-embryonic stage cell culture. We have developed an efficient and technically simple method for large-scale isolation and primary culture of larval-stage cells. We have optimized the treatment to maximize cell number and minimize cell death for each of the four larval stages. We obtained up to 7.8×10(4 cells per microliter of packed larvae, and up to 97% of adherent cells isolated by this method were viable for at least 16 hours. Cultured larval cells showed stage-specific increases in both cell size and multinuclearity and expressed lineage- and cell type-specific reporters. The majority (81% of larval cells isolated by our method were muscle cells that exhibited stage-specific phenotypes. L1 muscle cells developed 1 to 2 wide cytoplasmic processes, while L4 muscle cells developed 4 to 14 processes of various thicknesses. L4 muscle cells developed bands of myosin heavy chain A thick filaments at the cell center and spontaneously contracted ex vivo. Neurons constituted less than 10% of the isolated cells and the majority of neurons developed one or more long, microtubule-rich protrusions that terminated in actin-rich growth cones. In addition to cells such as muscle and neuron that are high abundance in vivo, we were also able to isolate M-lineage cells that constitute less than 0.2% of cells in vivo. Our novel method of cell isolation extends C. elegans cell culture to larval developmental stages, and allows use of the wealth of cell culture tools, such as cell sorting, electrophysiology, co-culture, and high-resolution imaging of subcellular dynamics, in investigation of post-embryonic development and physiology.

  8. Larval and post-larval stages of Pacific oyster (Crassostrea gigas are resistant to elevated CO2.

    Directory of Open Access Journals (Sweden)

    Ko W K Ginger

    Full Text Available The average pH of surface oceans has decreased by 0.1 unit since industrialization and is expected to decrease by another 0.3-0.7 units before the year 2300 due to the absorption of anthropogenic CO2. This human-caused pH change is posing serious threats and challenges to the Pacific oyster (Crassostrea gigas, especially to their larval stages. Our knowledge of the effect of reduced pH on C. gigas larvae presently relies presumptively on four short-term (<4 days survival and growth studies. Using multiple physiological measurements and life stages, the effects of long-term (40 days exposure to pH 8.1, 7.7 and 7.4 on larval shell growth, metamorphosis, respiration and filtration rates at the time of metamorphosis, along with the juvenile shell growth and structure of the C. gigas, were examined in this study. The mean survival and growth rates were not affected by pH. The metabolic, feeding and metamorphosis rates of pediveliger larvae were similar, between pH 8.1 and 7.7. The pediveligers at pH 7.4 showed reduced weight-specific metabolic and filtration rates, yet were able to sustain a more rapid post-settlement growth rate. However, no evidence suggested that low pH treatments resulted in alterations to the shell ultrastructures (SEM images or elemental compositions (i.e., Mg/Ca and Sr/Ca ratios. Thus, larval and post-larval forms of the C. gigas in the Yellow Sea are probably resistant to elevated CO2 and decreased near-future pH scenarios. The pre-adapted ability to resist a wide range of decreased pH may provide C. gigas with the necessary tolerance to withstand rapid pH changes over the coming century.

  9. Application of electrophoretic analysis on detecting the predation of Pardosa astrigera to Plutella maculipennis Curtis%星豹蛛对小菜蛾捕食作用的电泳检测研究

    Institute of Scientific and Technical Information of China (English)

    王宁波; 李生才

    2006-01-01

    本研究应用聚丙烯酰胺凝胶电泳技术,对星豹蛛雌雄蛛(Pardosa astrigera)捕食猎物小菜蛾(Plutella maculipennis Curtis)前后酯酶同工酶的变化进行了电泳分析.结果表明,在星豹蛛体内可以检测到被捕食猎物的特有酯酶同工酶酶带,且雌蛛最佳检测时间为捕食后3~6h,雄蛛为6~9h,猎物在星豹蛛雌蛛体内的消化时间短于雄蛛.

  10. Larval green and white sturgeon swimming performance in relation to water-diversion flows

    OpenAIRE

    Verhille, Christine E.; Poletto, Jamilynn B.; Cocherell, Dennis E.; DeCourten, Bethany; Baird, Sarah; Joseph J Cech; Fangue, Nann A.

    2014-01-01

    Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento–San Joaquin watershed, making them logical species to examine vulnerability to entrainment by altered water flows. The risk of larval sturgeon entrainment...

  11. Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

    Science.gov (United States)

    Donahue, Megan J; Karnauskas, Mandy; Toews, Carl; Paris, Claire B

    2015-01-01

    Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean) larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

  12. Cardiorespiratory ontogeny and response to environmental hypoxia of larval spiny lobster, Sagmariasus verreauxi.

    Science.gov (United States)

    Fitzgibbon, Quinn P; Ruff, Nicole; Battaglene, Stephen C

    2015-06-01

    Cardiorespiratory function is vital to an organism's ability to respond to environmental stress and analysis of cardiorespiratory capacity of species or life stages can elucidate vulnerability to climate change. Spiny lobsters have one of the most complex pelagic larval life cycles of any invertebrate and recently there has been an unexplained decline in post-larval recruitment for a number of species. We conducted the first analysis of the larval ontogeny of oxygen consumption, heart rate, maxilla 2 ventilation rate and oxyregulatory capacity of the spiny lobster, Sagmariasus verreauxi, to gain insight into their vulnerability to ocean change and to investigate life stage specific sensitivity to temperature-dependent oxygen limitation. In normoxia, heart and maxilla 2 ventilation rates increased in early larval development before declining, which we hypothesise is related to the transition from myogenic to neurogenic cardiac control. Maxilla 2 ventilation rate was sensitive to hypoxia at all larval stages, while heart rate was only sensitive to hypoxia in the late phyllosoma stages. Oxygen consumption conformed to environmental hypoxia at all larval stages. Spiny lobster larvae have limited respiratory control due to immature gas exchange physiology, compounded by their exceptionally large size. The lack of oxyregulatory ability suggests that all development stages are vulnerable to changes in sea temperature and oxygen availability. The synergetic stressors of increased temperature and reduced dissolved oxygen in the marine environment will diminish spiny lobster larval performance, increasing the challenge to achieve their extended larval life cycle, which may contribute to declines in post-larval recruitment.

  13. Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

    Directory of Open Access Journals (Sweden)

    Megan J Donahue

    Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

  14. Scanning electron microscopy of larval instars and imago of Oestrus caucasicus (Grunin, 1948 (Diptera: Oestridae

    Directory of Open Access Journals (Sweden)

    Guitton C.

    2001-06-01

    Full Text Available Oestrus caucasicus (Grunin, 1948 is a larval parasite of the nasal cavities of Capra caucasica, Capra ibex and Capra pyrenaica. This study is the first description of the parasite using scanning electron microscopy. The first larval instar shows minor differences with Oestrus ovis. The second larval instar shows important synapomorphic features common to Oestrus ovis but, also, distinctive features as the spines-crown or the currycomb-shaped spines. The third larval instar shows many differences with Oestrus ovis, mostly in the ventral and dorsal spines. The imagos of the two species have closely related morphologies. This study is a contribution to a revision of phylogeny of Oestridae family.

  15. Rising CO2 concentrations affect settlement behaviour of larval damselfishes

    Science.gov (United States)

    Devine, B. M.; Munday, P. L.; Jones, G. P.

    2012-03-01

    Reef fish larvae actively select preferred benthic habitat, relying on olfactory, visual and acoustic cues to discriminate between microhabitats at settlement. Recent studies show exposure to elevated carbon dioxide (CO2) impairs olfactory cue recognition in larval reef fishes. However, whether this alters the behaviour of settling fish or disrupts habitat selection is unknown. Here, the effect of elevated CO2 on larval behaviour and habitat selection at settlement was tested in three species of damselfishes (family Pomacentridae) that differ in their pattern of habitat use: Pomacentrus amboinensis (a habitat generalist), Pomacentrus chrysurus (a rubble specialist) and Pomacentrus moluccensis (a live coral specialist). Settlement-stage larvae were exposed to current-day CO2 levels or CO2 concentrations that could occur by 2100 (700 and 850 ppm) based on IPCC emission scenarios. First, pair-wise choice tests were performed using a two-channel flume chamber to test olfactory discrimination between hard coral, soft coral and coral rubble habitats. The habitat selected by settling fish was then compared among treatments using a multi-choice settlement experiment conducted overnight. Finally, settlement timing between treatments was compared across two lunar cycles for one of the species, P. chrysurus. Exposure to elevated CO2 disrupted the ability of larvae to discriminate between habitat odours in olfactory trials. However, this had no effect on the habitats selected at settlement when all sensory cues were available. The timing of settlement was dramatically altered by CO2 exposure, with control fish exhibiting peak settlement around the new moon, whereas fish exposed to 850 ppm CO2 displaying highest settlement rates around the full moon. These results suggest larvae can rely on other sensory information, such as visual cues, to compensate for impaired olfactory ability when selecting settlement habitat at small spatial scales. However, rising CO2 could cause larvae

  16. Ocean acidification alters temperature and salinity preferences in larval fish.

    Science.gov (United States)

    Pistevos, Jennifer C A; Nagelkerken, Ivan; Rossi, Tullio; Connell, Sean D

    2017-02-01

    Ocean acidification alters the way in which animals perceive and respond to their world by affecting a variety of senses such as audition, olfaction, vision and pH sensing. Marine species rely on other senses as well, but we know little of how these might be affected by ocean acidification. We tested whether ocean acidification can alter the preference for physicochemical cues used for dispersal between ocean and estuarine environments. We experimentally assessed the behavioural response of a larval fish (Lates calcarifer) to elevated temperature and reduced salinity, including estuarine water of multiple cues for detecting settlement habitat. Larval fish raised under elevated CO2 concentrations were attracted by warmer water, but temperature had no effect on fish raised in contemporary CO2 concentrations. In contrast, contemporary larvae were deterred by lower salinity water, where CO2-treated fish showed no such response. Natural estuarine water-of higher temperature, lower salinity, and containing estuarine olfactory cues-was only preferred by fish treated under forecasted high CO2 conditions. We show for the first time that attraction by larval fish towards physicochemical cues can be altered by ocean acidification. Such alterations to perception and evaluation of environmental cues during the critical process of dispersal can potentially have implications for ensuing recruitment and population replenishment. Our study not only shows that freshwater species that spend part of their life cycle in the ocean might also be affected by ocean acidification, but that behavioural responses towards key physicochemical cues can also be negated through elevated CO2 from human emissions.

  17. The use of immunostimulants in fish larval aquaculture.

    Science.gov (United States)

    Bricknell, Ian; Dalmo, Roy A

    2005-11-01

    The production of fish larvae is often hampered by high mortality rates, and it is believed that most of this economic loss due to infectious diseases is ca. 10% in Western European aquaculture sector. The development of strategies to control the pathogen load and immuno-prophylactic measures must be addressed further to realise the economic "potential" production of marine fish larvae and thus improve the overall production of adult fish. The innate defence includes both humoral and cellular defence mechanisms such as the complement system and the processes played by granulocytes and macrophages. A set of different substances such as beta-glucans, bacterial products, and plant constituents may directly initiate activation of the innate defence mechanisms acting on receptors and triggering intracellular gene activation that may result in production of anti-microbial molecules. These immunostimulants are often obtained from bacterial sources, brown or red algae and terrestrial fungi are also exploited as source of novel potentiating substances. The use of immunostimulants, as dietary supplements, can improve the innate defence of animals providing resistance to pathogens during periods of high stress, such as grading, reproduction, sea transfer and vaccination. The immunomodulation of larval fish has been proposed as a potential method for improving larval survival by increasing the innate responses of the developing animals until its adaptive immune response is sufficiently developed to mount an effective response to the pathogen. To this end it has been proposed that the delivery of immunostimulants as a dietary supplement to larval fish could be of considerable benefit in boosting the animals innate defences with little detriment to the developing animal. Conversely, there is a school of thought that raises the concern of immunomodulating a neotanous animal before its immune system is fully formed as this may adversely affect the development of a normal immune

  18. Catching large herring larvae: Gear applicability and larval distribution

    DEFF Research Database (Denmark)

    Munk, Peter

    1988-01-01

    given to the influence of gear speed on catching effectiveness. An additional objective was to investigate larval distributional patterns of potential importance to sampling strategy. Gear speed had a pronounced influence on the efficiency of the IKMT. Catches per unit volume filtered decreased to one...... third when speed was increased by one knot. The efficiency of the MIK did not change in the speed range investigated, and this gear was in every case more efficient than the IKMT. Larvae were found to be patchily distributed at the scale of sampling, and the degree of patchiness did not increase when...

  19. Parasites of larval black flies (Diptera: Simuliidae in Thailand

    Directory of Open Access Journals (Sweden)

    Sanae Jitklang

    2012-12-01

    Full Text Available Parasites of larval black flies are reported for the first time from Thailand, including mermithid nematodes(Mermithidae, microsporidian fungi (Zygomycota, and the fungus Coelomycidium simulii Debaisieux (Blastocladiomycetes.The following nine species of black flies were infected with one or more parasites: Simulium asakoae, S. chamlongi,S. chiangmaiense, S. fenestratum, S. feuerborni, S. nakhonense, S. nodosum, S. quinquestriatum, and S. tani. The prevalenceof patent infections per host species per season was 0.1–7.1% for mermithids, 0.1–6.0% for microsporidia, and 0.1–3.0% forC. simulii.

  20. The importance of accounting for larval detectability in mosquito habitat-association studies.

    Science.gov (United States)

    Low, Matthew; Tsegaye, Admasu Tassew; Ignell, Rickard; Hill, Sharon; Elleby, Rasmus; Feltelius, Vilhelm; Hopkins, Richard

    2016-05-04

    Mosquito habitat-association studies are an important basis for disease control programmes and/or vector distribution models. However, studies do not explicitly account for incomplete detection during larval presence and abundance surveys, with potential for significant biases because of environmental influences on larval behaviour and sampling efficiency. Data were used from a dip-sampling study for Anopheles larvae in Ethiopia to evaluate the effect of six factors previously associated with larval sampling (riparian vegetation, direct sunshine, algae, water depth, pH and temperature) on larval presence and detectability. Comparisons were made between: (i) a presence-absence logistic regression where samples were pooled at the site level and detectability ignored, (ii) a success versus trials binomial model, and (iii) a presence-detection mixture model that separately estimated presence and detection, and fitted different explanatory variables to these estimations. Riparian vegetation was consistently highlighted as important, strongly suggesting it explains larval presence (-). However, depending on how larval detectability was estimated, the other factors showed large variations in their statistical importance. The presence-detection mixture model provided strong evidence that larval detectability was influenced by sunshine and water temperature (+), with weaker evidence for algae (+) and water depth (-). For larval presence, there was also some evidence that water depth (-) and pH (+) influenced site occupation. The number of dip-samples needed to determine if larvae were likely present at a site was condition dependent: with sunshine and warm water requiring only two dips, while cooler water and cloud cover required 11. Environmental factors influence true larval presence and larval detectability differentially when sampling in field conditions. Researchers need to be more aware of the limitations and possible biases in different analytical approaches used to

  1. Effect of Larval Density on Food Utilization Efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae).

    Science.gov (United States)

    Morales-Ramos, Juan A; Rojas, M Guadalupe

    2015-10-01

    Crowding conditions of larvae may have a significant impact on commercial production efficiency of some insects, such as Tenebrio molitor L. (Coleoptera: Tenebrionidae). Although larval densities are known to affect developmental time and growth in T. molitor, no reports were found on the effects of crowding on food utilization. The effect of larval density on food utilization efficiency of T. molitor larvae was studied by measuring efficiency of ingested food conversion (ECI), efficiency of digested food conversion (EDC), and mg of larval weight gain per gram of food consumed (LWGpFC) at increasing larval densities (12, 24, 36, 48, 50, 62, 74, and 96 larvae per dm(2)) over four consecutive 3-wk periods. Individual larval weight gain and food consumption were negatively impacted by larval density. Similarly, ECI, ECD, and LWGpFC were negatively impacted by larval density. Larval ageing, measured as four consecutive 3-wk periods, significantly and independently impacted ECI, ECD, and LWGpFC in a negative way. General linear model analysis showed that age had a higher impact than density on food utilization parameters of T. molitor larvae. Larval growth was determined to be responsible for the age effects, as measurements of larval mass density (in grams of larvae per dm(2)) had a significant impact on food utilization parameters across ages and density treatments (in number of larvae per dm(2)). The importance of mass versus numbers per unit of area as measurements of larval density and the implications of negative effects of density on food utilization for insect biomass production are discussed.

  2. Maternal cortisol stimulates neurogenesis and affects larval behaviour in zebrafish

    Science.gov (United States)

    Best, Carol; Kurrasch, Deborah M.; Vijayan, Mathilakath M.

    2017-01-01

    Excess glucocorticoid transferred from stressed mother to the embryo affects developing vertebrate offspring, but the underlying programming events are unclear. In this study, we tested the hypothesis that increased zygotic glucocorticoid deposition, mimicking a maternal stress scenario, modifies early brain development and larval behaviour in zebrafish (Danio rerio). Cortisol was microinjected into the yolk at one cell-stage, to mimic maternal transfer, and the larvae [96 hours post-fertilization (hpf)] displayed increased activity in light and a reduction in thigmotaxis, a behavioural model for anxiety, suggesting an increased propensity for boldness. This cortisol-mediated behavioural phenotype corresponded with an increase in primary neurogenesis, as measured by incorporation of EdU at 24 hpf, in a region-specific manner in the preoptic region and the pallium, the teleostean homolog of the hippocampus. Also, cortisol increased the expression of the proneural gene neurod4, a marker of neurogenesis, in a region- and development-specific manner in the embryos. Altogether, excess zygotic cortisol, mimicking maternal stress, affects early brain development and behavioural phenotype in larval zebrafish. We propose a key role for cortisol in altering brain development leading to enhanced boldness, which may be beneficial in preparing the offspring to a stressful environment and enhancing fitness. PMID:28098234

  3. Assessing larval connectivity for marine spatial planning in the Adriatic.

    Science.gov (United States)

    Bray, L; Kassis, D; Hall-Spencer, J M

    2017-04-01

    There are plans to start building offshore marine renewable energy devices throughout the Mediterranean and the Adriatic has been identified as a key location for wind farm developments. The development of offshore wind farms in the area would provide hard substrata for the settlement of sessile benthos. Since the seafloor of the Adriatic is predominantly sedimentary this may alter the larval connectivity of benthic populations in the region. Here, we simulated the release of larvae from benthic populations along the coasts of the Adriatic Sea using coupled bio-physical models and investigated the effect of pelagic larval duration on dispersal. Our model simulations show that currents typically carry particles from east to west across the Adriatic, whereas particles released along western coasts tend to remain there with the Puglia coast of Italy acting as a sink for larvae from benthic populations. We identify areas of high connectivity, as well as areas that are much more isolated, and discuss how these results can be used to inform marine spatial planning and the licensing of offshore marine renewable energy developments.

  4. Chemical mediation of coral larval settlement by crustose coralline algae.

    Science.gov (United States)

    Tebben, J; Motti, C A; Siboni, Nahshon; Tapiolas, D M; Negri, A P; Schupp, P J; Kitamura, Makoto; Hatta, Masayuki; Steinberg, P D; Harder, T

    2015-06-04

    The majority of marine invertebrates produce dispersive larvae which, in order to complete their life cycles, must attach and metamorphose into benthic forms. This process, collectively referred to as settlement, is often guided by habitat-specific cues. While the sources of such cues are well known, the links between their biological activity, chemical identity, presence and quantification in situ are largely missing. Previous work on coral larval settlement in vitro has shown widespread induction by crustose coralline algae (CCA) and in particular their associated bacteria. However, we found that bacterial biofilms on CCA did not initiate ecologically realistic settlement responses in larvae of 11 hard coral species from Australia, Guam, Singapore and Japan. We instead found that algal chemical cues induce identical behavioral responses of larvae as per live CCA. We identified two classes of CCA cell wall-associated compounds--glycoglycerolipids and polysaccharides--as the main constituents of settlement inducing fractions. These algae-derived fractions induce settlement and metamorphosis at equivalent concentrations as present in CCA, both in small scale laboratory assays and under flow-through conditions, suggesting their ability to act in an ecologically relevant fashion to steer larval settlement of corals. Both compound classes were readily detected in natural samples.

  5. Maternal cortisol stimulates neurogenesis and affects larval behaviour in zebrafish.

    Science.gov (United States)

    Best, Carol; Kurrasch, Deborah M; Vijayan, Mathilakath M

    2017-01-18

    Excess glucocorticoid transferred from stressed mother to the embryo affects developing vertebrate offspring, but the underlying programming events are unclear. In this study, we tested the hypothesis that increased zygotic glucocorticoid deposition, mimicking a maternal stress scenario, modifies early brain development and larval behaviour in zebrafish (Danio rerio). Cortisol was microinjected into the yolk at one cell-stage, to mimic maternal transfer, and the larvae [96 hours post-fertilization (hpf)] displayed increased activity in light and a reduction in thigmotaxis, a behavioural model for anxiety, suggesting an increased propensity for boldness. This cortisol-mediated behavioural phenotype corresponded with an increase in primary neurogenesis, as measured by incorporation of EdU at 24 hpf, in a region-specific manner in the preoptic region and the pallium, the teleostean homolog of the hippocampus. Also, cortisol increased the expression of the proneural gene neurod4, a marker of neurogenesis, in a region- and development-specific manner in the embryos. Altogether, excess zygotic cortisol, mimicking maternal stress, affects early brain development and behavioural phenotype in larval zebrafish. We propose a key role for cortisol in altering brain development leading to enhanced boldness, which may be beneficial in preparing the offspring to a stressful environment and enhancing fitness.

  6. Larval habitats of mosquito fauna in Osogbo metropolis, Southwestern Nigeria

    Institute of Scientific and Technical Information of China (English)

    Monsuru Adebayo Adeleke; Wasiu Olalekan Adebimpe; AbdulWasiu Oladele Hassan; Sunday Olukayode Oladejo; Ismail Olaoye; Ganiyu Olatunji Olatunde; Taiwo Adewole

    2013-01-01

    Objective:To determine the larval habitats of mosquito fauna and possible impact of land use/land cover changes on the epidemiology of mosquito-borne diseases in Osogbo metropolis, Southwestern, Nigeria. Methods: All accessible larval habitats were surveyed between May and September, 2011 in Osogbo metropolis while Land Use/ Land cover of the city was analyzed using 2 Lansat Multispectral Scanner satellite imagery of SPOT 1986 and LANDSAT TM 2009. Results:A total of six species namely, Aedes aegypti, Aedes albopictus, Aedes vittatus, Anopheles gambiae complex, Culex quinquefasciatus and Eretmapodite chrysogaster were encountered during the study. The occurrence and contribution of disused tyres was significantly higher (P0.05). The accessible land use/land covered of the study area between 1986 and 2009 showed that the wet land coverage and settlement area increased from 0.19 to 9.09 hectare and 1.00 to 2.01 hectare respectively while the forest area decreased from 60.18 to 50.14 hectare. Conclusion: The contribution of the habitats coupled with the increasing rate of flooded environment which could provide ample breeding sites for mosquitoes call for sustained environmental sanitation and management in Osogbo metropolis.

  7. An accurate method for measuring triploidy of larval fish spawns

    Science.gov (United States)

    Jenkins, Jill A.; Draugelis-Dale, Rassa O.; Glennon, Robert; Kelly, Anita; Brown, Bonnie L.; Morrison, John

    2017-01-01

    A standard flow cytometric protocol was developed for estimating triploid induction in batches of larval fish. Polyploid induction treatments are not guaranteed to be 100% efficient, thus the ability to quantify the proportion of triploid larvae generated by a particular treatment helps managers to stock high-percentage spawns and researchers to select treatments for efficient triploid induction. At 3 d posthatch, individual Grass Carp Ctenopharyngodon idella were mechanically dissociated into single-cell suspensions; nuclear DNA was stained with propidium iodide then analyzed by flow cytometry. Following ploidy identification of individuals, aliquots of diploid and triploid cell suspensions were mixed to generate 15 levels (0–100%) of known triploidy (n = 10). Using either 20 or 50 larvae per level, the observed triploid percentages were lower than the known, actual values. Using nonlinear regression analyses, quadratic equations solved for triploid proportions in mixed samples and corresponding estimation reference plots allowed for predicting triploidy. Thus, an accurate prediction of the proportion of triploids in a spawn can be made by following a standard larval processing and analysis protocol with either 20 or 50 larvae from a single spawn, coupled with applying the quadratic equations or reference plots to observed flow cytometry results. Due to the universality of triploid DNA content being 1.5 times the diploid level and because triploid fish consist of fewer cells than diploids, this method should be applicable to other produced triploid fish species, and it may be adapted for use with bivalves or other species where batch analysis is appropriate.

  8. Development of environmental tools for anopheline larval control.

    Science.gov (United States)

    Imbahale, Susan S; Mweresa, Collins K; Takken, Willem; Mukabana, Wolfgang R

    2011-07-06

    Malaria mosquitoes spend a considerable part of their life in the aquatic stage, rendering them vulnerable to interventions directed to aquatic habitats. Recent successes of mosquito larval control have been reported using environmental and biological tools. Here, we report the effects of shading by plants and biological control agents on the development and survival of anopheline and culicine mosquito larvae in man-made natural habitats in western Kenya. Trials consisted of environmental manipulation using locally available plants, the introduction of predatory fish and/or the use of Bacillus thuringiensis var. israelensis (Bti) in various combinations. Man-made habitats provided with shade from different crop species produced significantly fewer larvae than those without shade especially for the malaria vector Anopheles gambiae. Larval control of the African malaria mosquito An. gambiae and other mosquito species was effective in habitats where both predatory fish and Bti were applied, than where the two biological control agents were administered independently. We conclude that integration of environmental management techniques using shade-providing plants and predatory fish and/or Bti are effective and sustainable tools for the control of malaria and other mosquito-borne disease vectors.

  9. Mosquito population regulation and larval source management in heterogeneous environments.

    Directory of Open Access Journals (Sweden)

    David L Smith

    Full Text Available An important question for mosquito population dynamics, mosquito-borne pathogen transmission and vector control is how mosquito populations are regulated. Here we develop simple models with heterogeneity in egg laying patterns and in the responses of larval populations to crowding in aquatic habitats. We use the models to evaluate how such heterogeneity affects mosquito population regulation and the effects of larval source management (LSM. We revisit the notion of a carrying capacity and show how heterogeneity changes our understanding of density dependence and the outcome of LSM. Crowding in and productivity of aquatic habitats is highly uneven unless egg-laying distributions are fine-tuned to match the distribution of habitats' carrying capacities. LSM reduces mosquito population density linearly with coverage if adult mosquitoes avoid laying eggs in treated habitats, but quadratically if eggs are laid in treated habitats and the effort is therefore wasted (i.e., treating 50% of habitat reduces mosquito density by approximately 75%. Unsurprisingly, targeting (i.e. treating a subset of the most productive pools gives much larger reductions for similar coverage, but with poor targeting, increasing coverage could increase adult mosquito population densities if eggs are laid in higher capacity habitats. Our analysis suggests that, in some contexts, LSM models that accounts for heterogeneity in production of adult mosquitoes provide theoretical support for pursuing mosquito-borne disease prevention through strategic and repeated application of modern larvicides.

  10. Patterns, causes, and consequences of marine larval dispersal.

    Science.gov (United States)

    D'Aloia, Cassidy C; Bogdanowicz, Steven M; Francis, Robin K; Majoris, John E; Harrison, Richard G; Buston, Peter M

    2015-11-10

    Quantifying the probability of larval exchange among marine populations is key to predicting local population dynamics and optimizing networks of marine protected areas. The pattern of connectivity among populations can be described by the measurement of a dispersal kernel. However, a statistically robust, empirical dispersal kernel has been lacking for any marine species. Here, we use genetic parentage analysis to quantify a dispersal kernel for the reef fish Elacatinus lori, demonstrating that dispersal declines exponentially with distance. The spatial scale of dispersal is an order of magnitude less than previous estimates-the median dispersal distance is just 1.7 km and no dispersal events exceed 16.4 km despite intensive sampling out to 30 km from source. Overlaid on this strong pattern is subtle spatial variation, but neither pelagic larval duration nor direction is associated with the probability of successful dispersal. Given the strong relationship between distance and dispersal, we show that distance-driven logistic models have strong power to predict dispersal probabilities. Moreover, connectivity matrices generated from these models are congruent with empirical estimates of spatial genetic structure, suggesting that the pattern of dispersal we uncovered reflects long-term patterns of gene flow. These results challenge assumptions regarding the spatial scale and presumed predictors of marine population connectivity. We conclude that if marine reserve networks aim to connect whole communities of fishes and conserve biodiversity broadly, then reserves that are close in space (<10 km) will accommodate those members of the community that are short-distance dispersers.

  11. Resource Limitation, Controphic Ostracod Density and Larval Mosquito Development.

    Directory of Open Access Journals (Sweden)

    Raylea Rowbottom

    Full Text Available Aquatic environments can be restricted with the amount of available food resources especially with changes to both abiotic and biotic conditions. Mosquito larvae, in particular, are sensitive to changes in food resources. Resource limitation through inter-, and intra-specific competition among mosquitoes are known to affect both their development and survival. However, much less is understood about the effects of non-culicid controphic competitors (species that share the same trophic level. To address this knowledge gap, we investigated and compared mosquito larval development, survival and adult size in two experiments, one with different densities of non-culicid controphic conditions and the other with altered resource conditions. We used Aedes camptorhynchus, a salt marsh breeding mosquito and a prominent vector for Ross River virus in Australia. Aedes camptorhynchus usually has few competitors due to its halo-tolerance and distribution in salt marshes. However, sympatric ostracod micro-crustaceans often co-occur within these salt marshes and can be found in dense populations, with field evidence suggesting exploitative competition for resources. Our experiments demonstrate resource limiting conditions caused significant increases in mosquito developmental times, decreased adult survival and decreased adult size. Overall, non-culicid exploitation experiments showed little effect on larval development and survival, but similar effects on adult size. We suggest that the alterations of adult traits owing to non-culicid controphic competition has potential to extend to vector-borne disease transmission.

  12. Larval fish dispersal in a coral-reef seascape

    KAUST Repository

    Almany, Glenn R.

    2017-05-23

    Larval dispersal is a critical yet enigmatic process in the persistence and productivity of marine metapopulations. Empirical data on larval dispersal remain scarce, hindering the use of spatial management tools in efforts to sustain ocean biodiversity and fisheries. Here we document dispersal among subpopulations of clownfish (Amphiprion percula) and butterflyfish (Chaetodon vagabundus) from eight sites across a large seascape (10,000 km2) in Papua New Guinea across 2 years. Dispersal of clownfish was consistent between years, with mean observed dispersal distances of 15 km and 10 km in 2009 and 2011, respectively. A Laplacian statistical distribution (the dispersal kernel) predicted a mean dispersal distance of 13–19 km, with 90% of settlement occurring within 31–43 km. Mean dispersal distances were considerably greater (43–64 km) for butterflyfish, with kernels declining only gradually from spawning locations. We demonstrate that dispersal can be measured on spatial scales sufficient to inform the design of and test the performance of marine reserve networks.

  13. The larval alimentary canal of the Antarctic insect, Belgica antarctica.

    Science.gov (United States)

    Nardi, James B; Miller, Lou Ann; Bee, Charles Mark; Lee, Richard E; Denlinger, David L

    2009-09-01

    On the Antarctica continent the wingless midge, Belgica antarctica (Diptera, Chironomidae) occurs further south than any other insect. The digestive tract of the larval stage of Belgica that inhabits this extreme environment and feeds in detritus of penguin rookeries has been described for the first time. Ingested food passes through a foregut lumen and into a stomodeal valve representing an intussusception of the foregut into the midgut. A sharp discontinuity in microvillar length occurs at an interface separating relatively long microvilli of the stomodeal midgut region, the site where peritrophic membrane originates, from the midgut epithelium lying posterior to this stomodeal region. Although shapes of cells along the length of this non-stomodeal midgut epithelium are similar, the lengths of their microvilli increase over two orders of magnitude from anterior midgut to posterior midgut. Infoldings of the basal membranes also account for a greatly expanded interface between midgut cells and the hemocoel. The epithelial cells of the hindgut seem to be specialized for exchange of water with their environment, with the anterior two-thirds of the hindgut showing highly convoluted luminal membranes and the posterior third having a highly convoluted basal surface. The lumen of the middle third of the hindgut has a dense population of resident bacteria. Regenerative cells are scattered throughout the larval midgut epithelium. These presumably represent stem cells for the adult midgut, while a ring of cells, marked by a discontinuity in nuclear size at the midgut-hindgut interface, presumably represents stem cells for the adult hindgut.

  14. Development of environmental tools for anopheline larval control

    Directory of Open Access Journals (Sweden)

    Mweresa Collins K

    2011-07-01

    Full Text Available Abstract Background Malaria mosquitoes spend a considerable part of their life in the aquatic stage, rendering them vulnerable to interventions directed to aquatic habitats. Recent successes of mosquito larval control have been reported using environmental and biological tools. Here, we report the effects of shading by plants and biological control agents on the development and survival of anopheline and culicine mosquito larvae in man-made natural habitats in western Kenya. Trials consisted of environmental manipulation using locally available plants, the introduction of predatory fish and/or the use of Bacillus thuringiensis var. israelensis (Bti in various combinations. Results Man-made habitats provided with shade from different crop species produced significantly fewer larvae than those without shade especially for the malaria vector Anopheles gambiae. Larval control of the African malaria mosquito An. gambiae and other mosquito species was effective in habitats where both predatory fish and Bti were applied, than where the two biological control agents were administered independently. Conclusion We conclude that integration of environmental management techniques using shade-providing plants and predatory fish and/or Bti are effective and sustainable tools for the control of malaria and other mosquito-borne disease vectors.

  15. Entomopathogenic fungi as biological control agents of diamondback moth (Lepidoptera: Plutellidae)and compatibility with chemical insecticides

    Science.gov (United States)

    The objectives were to evaluate the efficiency of entomopathogenic fungi against Plutella xylostella (L.) and the compatibility of the most virulent isolates with some of the insecticides registered for use on cabbage crops. Pathogenicity tests used isolates of Beauveria bassiana, Metarhizium rileyi...

  16. Oviposition of diamondback moth in the presence and absence of a novel host plant

    NARCIS (Netherlands)

    Henniges-Janssen, K; Schöfl, G.; Reineke, A.; Heckel, D.G.; Groot, A.T.

    2011-01-01

    The diamondback moth (DBM, Plutella xylostella L. (Lepidoptera: Plutellidae)) consumes a wide variety of brassicaceous host plants and is a common pest of crucifer crops worldwide. A highly unusual infestation of a sugar pea crop was recorded in Kenya in 1999, which persisted for two consecutive yea

  17. Triterpenoid Saponin Biosynthesis in the non-model Crucifer Plant Barbares Vulgaris

    DEFF Research Database (Denmark)

    Erthmann, Pernille Østerbye

    are identified and found to be responsible for resistance towards flea beetles (Phyllotreta nemorum) and diamondback moths (Plutella xylostella). Genes involved in the biosynthesis of these saponins were recently identified, however the complete biosynthetic pathway is not known to date. These findings set...

  18. Variation in plant volatiles and attraction of the parasitoid Diadegma semiclausum (Hellén)

    NARCIS (Netherlands)

    Bukovinszky, T.; Gols, R.; Posthumus, M.A.; Vet, L.E.M.; Van Lenteren, J.C.

    2005-01-01

    Differences in allelochemistry of plants may influence their ability to attract parasitoids.We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter- and intraspecific variation in odor blends of crucifers and a non-crucifer speci

  19. Intra-specific variation in wild Brassica oleracea for aphid-induced plant responses and consequences for caterpillar–parasitoid interactions

    NARCIS (Netherlands)

    Li, Y.; Dicke, M.; Harvey, J.A.; Gols, R.

    2014-01-01

    [KEYWORDS: Cabbage Diadegma semiclausum Herbivory Leaf chewers Mamestra brassicae Microplitis mediator Plutella xylostella phloem feeders] Herbivore-induced plant responses not only influence the initiating attackers, but also other herbivores feeding on the same host plant simultaneously or at a di

  20. Dicty_cDB: Contig-U06672-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .4 FJ227128_48( FJ227128 |pid:none) Euproctis pseudoconspersa nucleop... 32 5.3 DQ325038_1( DQ325038 |pid:none) Apis dorsata compleme...ntary sex det... 32 6.9 AF270937_43( AF270937 |pid:none) Plutella xylostella granul

  1. Numerical simulations of barnacle larval dispersion coupled with field observations on larval abundance, settlement and recruitment in a tropical monsoon influenced coastal marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Samiksha S.V.; George, G.; Aboobacker V.M.; Vethamony, P.; Anil, A.C.

    different circumstances. Environmental variability is the main cause for such differences. Larvae are likely to disperse or retain more without settling behavior or mortality factors. Factors such as food availability and predation can also influence... both feeding as well as non-feeding stages, success of larval populations depends on its dispersal/retention to habitats with sufficient food. The non-feeding larval stage (cyprids) can last for several days depending on the stored energy content...

  2. Influences of acid mine drainage and thermal enrichment on stream fish reproduction and larval survival

    Science.gov (United States)

    Hafs, Andrew W.; Horn, C.D.; Mazik, P.M.; Hartman, K.J.

    2010-01-01

    Potential effects of acid mine drainage (AMD) and thermal enrichment on the reproduction of fishes were investigated through a larval-trapping survey in the Stony River watershed, Grant County, WV. Trapping was conducted at seven sites from 26 March to 2 July 2004. Overall larval catch was low (379 individuals in 220 hours of trapping). More larval White Suckers were captured than all other species. Vectors fitted to nonparametric multidimensional scaling ordinations suggested that temperature was highly correlated to fish communities captured at our sites. Survival of larval Fathead Minnows was examined in situ at six sites from 13 May to 11 June 2004 in the same system. Larval survival was lower, but not significantly different between sites directly downstream of AMD-impacted tributaries (40% survival) and non-AMD sites (52% survival). The lower survival was caused by a significant mortality event at one site that coincided with acute pH depression in an AMD tributary immediately upstream of the site. Results from a Cox proportional hazard test suggests that low pH is having a significant negative influence on larval fish survival in this system. The results from this research indicate that the combination of low pH events and elevated temperature are negatively influencing the larval fish populations of the Stony River watershed. Management actions that address these problems would have the potential to substantially increase both reproduction rates and larval survival, therefore greatly enhancing the fishery.

  3. Larval developmental rate, metabolic rate and future growth performance in Atlantic salmon

    DEFF Research Database (Denmark)

    Serrano, Jonathan Vaz; Åberg, Madelene; Gjoen, Hans Magnus;

    2009-01-01

    Previous studies in salmonids suggest a link between larval developmental rate, metabolic rate, and future growth. However, the connection between growth during exogenous and endogenous feeding is still debated. In the current study, a positive relationship between larval developmental rate, quan...

  4. Batch fertility and larval parameters of the jaguar cichlid (Cichlasoma managuense spawned in the laboratory (ESP

    Directory of Open Access Journals (Sweden)

    Jorge Günther Nonell

    2016-03-01

    Full Text Available Batch fertility and larval parameters of 32 spawns of the jaguar guapote (Cichlasoma managuense in the laboratory were analyzed. Batch fertility was positively correlated with the female weight with spawns between about 3000 to 6000 larvae for females between 100 and 500 g wet weight. No significant correlation was found between larval parameters (fresh weight and % dry weight and female weight.

  5. Ascorbic Acid Influences the Development and Immunocompetence of Larval Heliothis virescens

    Science.gov (United States)

    We report that ascorbic acid, which is known to be a free radical scavenger, to be important not only in insect development but also in larval resistance to baculovirus infection. We sequentially elevated the ascorbic acid content in diet and evaluated the effect on larval H. virescens development ...

  6. Clutch size in a larval-pupal endoparasitoid: Consequences for fitness

    NARCIS (Netherlands)

    Vet, L.E.M.; Datema, A.; Janssen, A.; Snellen, H.

    1994-01-01

    1. Aphaereta minuta (Hymenoptera: Braconidae) is a gregarious larval-pupal endoparasitoid of many Diptera species. Several larval instars can be parasitized and the size differences between host species can be considerable. After parasitization, however, the host larva continues to grow and the

  7. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi

    NARCIS (Netherlands)

    Vogels, C.B.F.; Bukhari, T.; Koenraadt, C.J.M.

    2014-01-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is af

  8. Utilization of larval and pupal detritus by Aedes aegypti and Aedes albopictus.

    Science.gov (United States)

    Bara, J J; Clark, T M; Remold, S K

    2014-06-01

    The utilization of detritus sources by mosquito larvae during development may significantly affect adult life history traits and mosquito population growth. Many studies have shown invertebrate carcasses to be an important detritus source in larval habitats, but little is known regarding how invertebrate carcasses are utilized by mosquito larvae. We conducted two studies to investigate the rate of detritus consumption and its effect on larval development and life history traits. Overall, we found that Aedes aegypti and Aedes albopictus larvae rapidly consumed larval detritus, while pupal detritus was consumed at a significantly slower rate. We also found that the consumption of larval detritus significantly increased larval survivorship and decreased male development time but did not significantly influence female development time or pupal cephalothorax length for either sex. Our results suggest that the direct consumption of larval detritus can support the production of adults in larval habitats that lack allochthonous detritus inputs or where such organic inputs are insufficient. These studies indicate that different forms of invertebrate detritus are utilized in distinct ways by mosquito larvae, and therefore different forms of invertebrate detritus may have distinct effects on larval development and adult life history traits. © 2014 The Society for Vector Ecology.

  9. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi

    NARCIS (Netherlands)

    Vogels, C.B.F.; Bukhari, T.; Koenraadt, C.J.M.

    2014-01-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is

  10. Differential growth of larval sprat Sprattus sprattus across a tidal front in the eastern North Sea

    DEFF Research Database (Denmark)

    Munk, Peter

    1993-01-01

    distributions of larval sprat were dominated by modes of 12 and 16 mm, and growth rates of these 2 size classes were estimated from a Laird-Gompertz curve of larval size at age. Size at age of larvae was estimated by analysis of sagittal otoliths. Growth rate estimates were highest in the mixed water (absolute...

  11. Biological Strategies of Dermestes maculatus DeGeer (Coleoptera: Dermestidae) at Larval Stages in Different Temperatures.

    Science.gov (United States)

    Zanetti, N I; Visciarelli, E C; Centeno, N D

    2016-12-01

    The intraspecific variation in larval instars is a widely distributed phenomenon amongst holometabolous insects. Several factors can affect the number of instars, such as temperature, humidity, and density. Only a few references could be found in the literature because the invariability in the number of larval instars is considered normal, and the issue has raised little to no interest. Despite this, no study to date has intended to assess or focus on the larval development. Here, we analyzed the effect of different rearing temperature on the larval stage of Dermestes maculatus DeGeer (Coleoptera: Dermestidae). The results indicated that at all temperatures, L5 represented a decisive point for individuals as well as the other later larval instars, because the next step to follow was to pupate or molt to the next larval instar. Furthermore, there were mainly two populations, L5 and L6, although in different proportions according to temperature. We also found that at a greater number of instars, the larval development at all temperatures lasted longer. Moreover, the exponential model was the best adjustment in the developmental time of all populations as well as for the accumulated developmental time of L1-L4. Thus, we conclude that random factors such as genetics could probably cause interspecific variability in D. maculatus larval development.

  12. Recruitment of the barnacle Balanus amphitrite Darwin in a tropical estuary: implications of environmental perturbation, reproduction and larval ecology

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, D.V.; Anil, A.C.

    variations in recruitment, larval abundance, development and reproduction. Adult conditioning and inter-brood variations were important factors in the larval ecology of this organism. The results indicate that the impulsive release of larvae during breaks...

  13. Descriptions of four larval forms of Nilodosis Kieffer from East Asia

    Directory of Open Access Journals (Sweden)

    Hongqu Tang

    2012-10-01

    Full Text Available Larval material putatively assigned to the genus Nilodosis Kieffer from Korea, China and Japan has been compared. The results show that the Japanese larval form has the club- to balloon-shaped cephalic setae S7 and S9 in common with the Korean larval form, but it can be separated from the latter by the shape of the inner mandibular teeth and the premandibular teeth. The larval forms from China (Guangdong and Yunnan apparently consist of two independent species. It is most likely that there will be more species in this genus found in Asia. Larvae are mud-sandy bottom-dwellers that can occur in the littoral of lakes and the potamal of larger rivers, up to a maximum depth of 5 meters. The specific larval characters show that it probably is a semi-psammorheophilic predator. doi: 10.5324/fn.v31i0.1406.Published online: 17 October 2012. 

  14. Modelling larval transport in a axial convergence front

    Science.gov (United States)

    Robins, P.

    2010-12-01

    Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

  15. Larval diapause termination in the bamboo borer, Omphisa fuscidentalis

    Science.gov (United States)

    Suang, Suphawan; Manaboon, Manaporn; Singtripop, Tippawan; Hiruma, Kiyoshi; Kaneko, Yu; Tiansawat, Pimonrat; Neumann, Peter; Chantawannakul, Panuwan

    2017-01-01

    In insects, juvenile hormone (JH) and 20-hydroxyecdysone (20E) regulate larval growth and molting. However, little is known about how this cooperative control is terminating larval diapause especially in the bamboo borer, Omphisa fuscidentalis. In both in vivo and in vitro experiments, we here measured the expression levels of genes which were affected by juvenile hormone analogue (JHA: S-methoprene) and 20-hydroxyecdysone (20E) in diapausing O. fuscidentalis larvae. Corresponding mRNA expression changes in the subesophageal ganglion (SG) and prothoracic gland (PG) were evaluated using qRT-PCR. The data showed similar response patterns of JH receptor gene (OfMet), diapause hormone gene (OfDH-PBAN), ecdysone receptor genes (OfEcR-A and OfEcR-B1) and ecdysone inducible genes (OfBr-C, OfE75A, OfE75B, OfE75C and OfHR3). JHA induced the expressions of OfMet and OfDH-PBAN in both SG and PG, whereas ecdysone receptor genes and ecdysone inducible genes were induced by JHA only in PG. For 20E treatment group, expressions of ecdysone receptor genes and ecdysone inducible genes in both SG and PG were increased by 20E injection. In addition, the in vitro experiments showed that OfMet and OfDH-PBAN were up-regulated by JHA alone, but ecdysone receptor genes and ecdysone inducible genes were up-regulated by JHA and 20E. However, OfMet and OfDH-PBAN in the SG was expressed faster than OfMet and OfDH-PBAN in the PG and the expression of ecdysone receptor genes and ecdysone inducible genes induced by JHA was much later than observed for 20E. These results indicate that JHA might stimulate the PG indirectly via factors (OfMet and OfDH-PBAN) in the SG, which might be a regulatory mechanism for larval diapause termination in O. fuscidentalis. PMID:28369111

  16. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Science.gov (United States)

    Pappalardo, Paula; Rodríguez-Serrano, Enrique; Fernández, Miriam

    2014-01-01

    Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule), which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding) development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in muricids gastropods.

  17. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Directory of Open Access Journals (Sweden)

    Paula Pappalardo

    Full Text Available Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule, which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in

  18. Newly-discovered muscle in the larva of Patella coerulea (Mollusca, Gastropoda) suggests the presence of a larval extensor

    NARCIS (Netherlands)

    Damen, Peter; Dictus, Wim J.A.G.

    2002-01-01

    The development of the muscular system of the gastropod mollusc Patella has been thoroughly studied. As a result, two larval retractors, the main and accessory larval retractor, had been described in the larva of Patella. These muscles were supposed to be responsible for the retraction of the larval

  19. Newly-discovered muscle in the larva of Patella coerulea (Mollusca, Gastropoda) suggests the presence of a larval extensor

    NARCIS (Netherlands)

    Damen, Peter; Dictus, Wim J.A.G.

    2002-01-01

    The development of the muscular system of the gastropod mollusc Patella has been thoroughly studied. As a result, two larval retractors, the main and accessory larval retractor, had been described in the larva of Patella. These muscles were supposed to be responsible for the retraction of the larval

  20. Feeding competition between larval lake whitefish and lake herring

    Science.gov (United States)

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

    The potential for competition for food between larval lake whitefish (Coregonus clupeaformis) and lake herring (C. artedi) 1- to 8-wk of age was explored in a series of 1-h laboratory feeding studies. Feeding started at 2-wk post-hatch. Learning and fish size appear to be more important than prey density at the onset of feeding. Species differed in their feeding behavior and consumption noticeably by 5-wk and substantially by 8-wk. Lake whitefish generally were more aggressive foragers than lake herring, attacking and capturing more prey. At high plankton density at 8-wk, lake herring feeding was depressed in mixed-fish treatments. This difference in competitive food consumption between the two coregonids occurs at a critical life stage, and when combined with other biotic and abiotic factors, may have a significant impact on recruitment.

  1. Embryonic and larval development of Brycon amazonicus (SPIX & AGASSIZ, 1829

    Directory of Open Access Journals (Sweden)

    A. C. S. Sampaio Nakauth

    Full Text Available Abstract The objective of this study was to describe the embryonic and larval development of Brycon amazonicus, featuring the main events up to 50 hours after fertilization (AF. The material was provided by the Aquaculture Training, Technology and Production Center, Presidente Figueiredo (AM. The characterization was based on stereomicroscopic examination of the morphology of eggs, embryos and larvae and comparison with the literature. Matrinxã eggs are free, transparent, and spherical, with a perivitelline space of 0.56 ± 0.3 mm. The successive divisions give rise to cells with 64 blastomeres during the first hour AF. The gastrula stage, beginning 02 h 40 min AF, was characterized by progressive regression cells and the formation of the embryonic axis, leading to differentiation of the head and tail 05 h 30 min AF. From 06 to 09 h AF the somites, notochord, otic and optic vesicles and otoliths were observed, in addition to heart rate and the release of the tail. The larvae hatched at 10 h 30 min AF (29.9 °C, with a total length of 3.56 ± 0.46 mm. Between 19 and 30 h AF, we observed 1 pigmentation and gut formation, 2 branchial arches, 3 pectoral fins, 4 a mouth opening and 5 teeth. Cannibalism was initiated earlier (34 h AF which was associated with rapid yolk absorption (more than 90% until 50 h AF, signaling the need for an exogenous nutritional source. The environmental conditions (especially temperature influenced the time course of some events throughout the embryonic and larval development, suggesting the need for further studies on this subject.

  2. The role of dopamine in Drosophila larval classical olfactory conditioning.

    Directory of Open Access Journals (Sweden)

    Mareike Selcho

    Full Text Available Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt as well as appetitive (odor-sugar associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive

  3. Influence of Physiological Stress on Nutrient Stoichiometry in Larval Amphibians.

    Science.gov (United States)

    Kirschman, Lucas J; Haslett, Savhannah; Fritz, Kelley A; Whiles, Matt R; Warne, Robin W

    2016-01-01

    Exposure to environmental stressors alters animal phenotypes as well as nutrient metabolism, assimilation, and excretion. While stress-induced shifts in nutrient processes are known to alter organismal carbon (C) and nitrogen (N) stoichiometry, there has been little exploration of how environmental factors influence phosphorous (P). A better understanding of how P cycling varies with animal physiological state may provide insight into across-scale processes, because P is essential to animal function and ecological processes such as production and decomposition. We tested the effects of predator stress and exogenous glucocorticoids on C∶N∶P stoichiometry of larval amphibians. Glucocorticoids altered nutrient stoichiometry, apparently by modulating ossification and renal function. This reduced whole-body P and significantly increased N∶P. Additionally, elevated glucocorticoids caused a long-term reduction in P excretion. This reduction may reflect an initial unmeasured loss of P that glucocorticoids induce over acute timescales. In contrast, exposure to predator cues had no effect on larval C∶N∶P stoichiometry, which highlights that different stressors have varied effects on the endocrine stress response. Predation, in particular, is ubiquitous in the environment; thus, larvae responding to predators have conserved mechanisms that likely prevent or minimize physiological disruption. These results demonstrate the differing physiological roles of N and P, distinct nutrient demands associated with amphibian metamorphosis, and the contrasting effects that different environmental factors have on the physiological stress response. Our results also suggest that anthropogenic changes to the environment that induce chronic stress in amphibians could affect the biogeochemistry of nutrient-poor environments where they may act as keystone species.

  4. Interactions between introduced trout and larval salamanders (Ambystoma macrodactylum) in high-elevation lakes

    Science.gov (United States)

    Tyler, T.; Liss, W.J.; Ganio, L.; Larson, Gary L.; Hoffman, Robert L.; Deimling, E.; Lomnicky, G.A.

    1998-01-01

    The larval stage of the long-toed salamander (Ambystoma macrodactylum) is the top vertebrate predator in high-elevation fishless lakes in the North Cascades National Park Service Complex, Washington (U.S.A.). Although most of these high-elevation lakes were naturally fishless, trout have been stocked in many of them. We sought to determine the effects of physicochemical factors and introduced trout on abundance and behavior of A. macrodactylum larvae. Larval salamander densities were estimated by snorkeling. Snorkelers carefully searched through substrate materials within 2 m of the shoreline and recorded the number of larvae observed and if larvae were hidden in benthic substrates. Physicochemical factors were measured in each lake on the same day that snorkel surveys were conducted. In fishless lakes, larval salamander densities were positively related to total Kjeldahl-N concentration and negatively related to lake elevation. Crustacean zooplankton, especially cladocerans, were important food resources for larval A. macrodactylum. Crustacean zooplankton and cladoceran densities were positively related to total Kjeldahl-N, suggesting that increased food resources contributed to increased densities of larval A. macrodactylum. Differences in larval salamander densities between fish and fishless lakes were related to total Kjeldahl-N concentrations and the reproductive status of trout. Mean larval salamander densities for fishless lakes with total Kjeldahl-N amphibians requires an understanding of natural abiotic and biotic factors and processes influencing amphibian distribution and abundance.

  5. Proteomics Insights: Proteins related to Larval Attachment and Metamorphosis of Marine Invertebrates

    Directory of Open Access Journals (Sweden)

    KONDETHIMMANAHALLI eCHANDRAMOULI

    2014-10-01

    Full Text Available The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTM are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  6. Proteomics insights: proteins related to larval attachment and metamorphosis of marine invertebrates

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2014-10-31

    The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTMs) are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  7. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2012-02-13

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  8. Susceptibility of cat fleas (Siphonaptera: Pulicidae) to fipronil and imidacloprid using adult and larval bioassays.

    Science.gov (United States)

    Rust, M K; Vetter, R; Denholm, I; Blagburn, B; Williamson, M S; Kopp, S; Coleman, G; Hostetler, J; Davis, W; Mencke, N; Rees, R; Foit, S; Tetzner, K

    2014-05-01

    The monitoring of the susceptibility offleas to insecticides has typically been conducted by exposing adults on treated surfaces. Other methods such as topical applications of insecticides to adults and larval bioassays on treated rearing media have been developed. Unfortunately, baseline responses of susceptible strains of cat flea, Ctenocephalides felis (Bouchè), except for imidacloprid, have not been determined for all on-animal therapies and new classes of chemistry now being used. However, the relationship between adult and larval bioassays of fleas has not been previously investigated. The adult and larval bioassays of fipronil and imidacloprid were compared for both field-collected isolates and laboratory strains. Adult topical bioassays of fipronil and imidacloprid to laboratory strains and field-collected isolates demonstrated that LD50s of fipronil and imidacloprid ranged from 0.11 to 0.40 nanograms per flea and 0.02 to 0.18 nanograms per flea, respectively. Resistance ratios for fipronil and imidacloprid ranged from 0.11 to 2.21. Based on the larval bioassay published for imidacloprid, a larval bioassay was established for fipronil and reported in this article. The ranges of the LC50s of fipronil and imidacloprid in the larval rearing media were 0.07-0.16 and 0.11-0.21 ppm, respectively. Resistance ratios for adult and larval bioassays ranged from 0.11 to 2.2 and 0.58 to 1.75, respectively. Both adult and larval bioassays provided similar patterns for fipronil and imidacloprid. Although the adult bioassays permitted a more precise dosage applied, the larval bioassays allowed for testing isolates without the need to maintain on synthetic or natural hosts.

  9. Larval intraspecific competition for food in the European grapevine moth Lobesia botrana.

    Science.gov (United States)

    Thiéry, D; Monceau, K; Moreau, J

    2014-08-01

    Effective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

  10. Expression of calmodulin and myosin light chain kinase during larval settlement of the Barnacle Balanus amphitrite.

    Directory of Open Access Journals (Sweden)

    Zhang-Fan Chen

    Full Text Available Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM and its binding proteins in the larval settlement of the barnacle, Balanus ( = Amphibalanus amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM, encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca(2+/CaM-dependent kinase II (CaMKII inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite.

  11. Does White Clover (Trifolium repens) Abundance in Temperate Pastures Determine Sitona obsoletus (Coleoptera: Curculionidae) Larval Populations?

    Science.gov (United States)

    McNeill, Mark R.; van Koten, Chikako; Cave, Vanessa M.; Chapman, David; Hodgson, Hamish

    2016-01-01

    To determine if host plant abundance determined the size of clover root weevil (CRW) Sitona obsoletus larval populations, a study was conducted over 4 years in plots sown in ryegrass (Lolium perenne) (cv. Nui) sown at either 6 or 30 kg/ha and white clover (Trifolium repens) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012–2015 were 310, 38, 59, and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012–2014 larval populations, observed densities tended to be higher than predicted, but the numbers came

  12. Prey size spectra and prey availability of larval and small juvenile cod

    DEFF Research Database (Denmark)

    Munk, Peter

    1997-01-01

    stage when viewed on a relative predator/prey size scale. The study is based on stomach analysis of larval/juvenile cod in the size range 10-35 mm from nursery grounds in the North Sea. Stomach contents (species, size) were compared to environmental composition and preference indices were calculated...... prey biomass was highest in the areas of a hydrographic front, where larvae have been shown to concentrate. Changes in prey availability with larval growth depend strongly on specific prey biomass spectra at a given location. Both increasing and decreasing prey availability al increasing larval size...

  13. Catching prey with the antennae - The larval head of Corethrella appendiculata (Diptera: Corethrellidae).

    Science.gov (United States)

    Förster, Maria; Beutel, Rolf G; Schneeberg, Katharina

    2016-11-01

    The larval cephalic morphology of Corethrella appendiculata Grabham, 1906 is described and documented in detail. The observed features are compared to conditions found in Chaoboridae, Culicidae, and other culicomorph families. The function of antennae, mouthparts and associated muscles is interpreted based on the morphological results. The prey catching mechanism is compared to what occurs in other predaceous larvae of Culicomorpha. The cephalic larval morphology is discussed with respect to homology and possible phylogenetic implications. The horizontal frontoclypeal antennal grooves and the lateral rows of strongly developed bristles are likely larval autapomorphies of Corethrellidae. The presence of raptorial antennae is a highly unusual apomorphy shared with Chaoboridae. The systematic position of Corethrellidae remains ambiguous.

  14. Does white clover (Trifolium repens abundance in temperate pastures determine Sitona obsoletus (Coleoptera: Curculionidae larval populations?

    Directory of Open Access Journals (Sweden)

    Mark Richard McNeill

    2016-09-01

    Full Text Available To determine if host plant abundance determined the size of clover root weevil (CRW Sitona obsoletus larval populations, a study was conducted over four years in plots sown in ryegrass (Lolium perenne (cv. Nui sown at either 6 or 30 kg/ha and white clover (Trifolium repens sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand with % clover measured in autumn (April and spring (September of each year. Overall, mean larval densities measured in spring 2012, 2013, 2014 and 2015 were 310, 38, 59 and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3 and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October larval populations to % white clover measured in each plot in autumn (April found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted

  15. Larval fish assemblages across an upwelling front: Indication for active and passive retention

    Science.gov (United States)

    Tiedemann, Maik; Brehmer, Patrice

    2017-03-01

    In upwelling areas, enrichment, concentration and retention are physical processes that have major consequences for larval fish survival. While these processes generally increase larval survival, strong upwelling can also increase mortality due to an offshore transport of larvae towards unfavorable habitats. In 2013 a survey was conducted along the Senegalese coast to investigate the upwelling effect with regard to larval fish assemblages and possible larval fish retention. According to water column characteristics two distinct habitats during an upwelling event were discriminated, i.e. the inshore upwelled water and the transition area over the deepest part of the Senegalese shelf. Along the two areas 42,162 fish larvae were collected representing 133 species within 40 families. Highest larval fish abundances were observed in the inshore area and decreasing abundances towards the transition, indicating that certain fish species make use of the retentive function of the inner shelf area as spawning grounds. Two larval fish assemblages overlap both habitats, which are sharply delimited by a strong upwelling front. One assemblage inhabited the inshore/upwelling area characterized by majorly neritic and pelagic species (Sparidae spp., Sardinella aurita), that seem to take the advantage of a passive retention on the shelf. The second assemblage consisted of a mix of pelagic and mesopelagic species (Engraulis encrasicolus, Carangidae spp. and Myctophidae spp.). Some species of the second assemblage, e.g. horse mackerels (Trachurus trachurus and Trachurus trecae), large finned-lantern fish (Hygophum macrochir) and foureyed sole (Microchirus ocellatus), revealed larval peak occurrences at intermediate and deep water layers, where the near-ground upwelling layer is able to transport larvae back to the shelf. This indicates active larval retention for species that are dominant in the transition area. Diel vertical migration patterns of S. aurita, E. encrasicolus and M

  16. The larval abdomen of the enigmatic Nannochoristidae (Mecoptera, Insecta).

    Science.gov (United States)

    Fraulob, Maximilian; Wipfler, Benjamin; Hünefeld, Frank; Pohl, Hans; Beutel, Rolf G

    2012-03-01

    External and internal structures of the larval abdomen of Nannochorista are described in detail, with emphasis on the posterior segments. The results are compared with conditions found in other groups of Antliophora, especially the mecopteran subgroups Boreidae and Pistillifera. Like the entire postcephalic body, the larval abdomen of Nannochorista is extremely slender and nearly cylindrical. The anterior segments are largely unmodified. The surface is smooth and lacks any protuberances or prolegs. The term "cloaca" for the posterior membranous pouch of Nannochorista sp. is morphologically unjustified. A list of muscles of segments IX and X is presented. The abdominal musculature was partly homologized following Snodgrass. The muscles of segment X are highly modified. They move the membranous pouch, the anal papillae, and the terminal lobes. The presence of these structures is likely an adaptation to the specific aquatic life style of nannochoristid larvae. The anal papillae are possibly homologous to the 4-lobed terminal attachment apparatus of larvae of Caurinus (Boreidae) and Pistillifera (Panorpidae, Bittacidae, Choristidae) but this is uncertain. The specific condition in both groups, i.e. two retractile papillae with tracheae and Malpighian tubules in Nannochoristidae, and a 4-lobed exposed attachment device in Pistillifera + Boreidae (groundplan) are very likely autapomorphic for both groups, respectively. A slender abdomen with smooth surface is very likely plesiomorphic within Antliophora and Mecopterida. This condition is found in Trichoptera (partim), Nannochoristidae, Siphonaptera, and many basal groups of Diptera. An eruciform or scarabaeiform body shape with a soft, largely unsclerotised cuticle is probably a synapomorphy of Boreidae and Pistillifera. The presence of ventral protuberances resembling prolegs on the anterior segments is an autapomorphy of the latter group. The homology of paired or unpaired terminal appendages of segment X is

  17. A larval dispersion study using lagrangian simulation of particles

    Directory of Open Access Journals (Sweden)

    Laura Rodríguez Díaz

    2014-06-01

    Full Text Available The continuous displacement of water allows stabilize the temperature and also distributes nutrients and plankton in the ocean and seas permitting the development of organisms and the transfers of larvae from the spawning areas to the habitat where adult fishes can be found. The area of study covers The North Atlantic Ocean so the principal aim of the study is analyze if released particles at the Florida Strait could cross the North Atlantic Ocean and reach the European shelf. To test this, it has simulated Lagrangian trajectories for different numbers of particles or "larvae" with a passive behavior (fixing at a depth of dispersion. It has analyzed the dispersion of those particles by using the data of the components U, V and W from the speed of currents provided by the database SODA which uses an ocean model based on Geophysical Fluid Dynamics Laboratory MOM2 and data profiles from World Ocean Atlas-94 and from Geosat, ERS-1 and TOPEX/Poseidon satellites. Considering the dispersive nature of the ocean, the simulations were performed by releasing many particles (typically of the order of several thousand and it was also necessary to perform an interpolation process in time and space so that the position of the particles could evolve. The simulations have been run with 5,000 particles and it has been considered a biological parameter (planktonic larval duration, PLD that represents the length of larval life. At this study it has been used PLD for a specific starfish larva (Sclerasterias tanneri larvae that can be found at the Gulf of Mexico at different locations. Particles were released in October at the most oceanward location of the Gulf of Mexico close to the Florida Strait where Sclerasterias tanneri larvae can be found. Those particles have been tracked for 660 days (660 days is the PLD of Sclerasterias tanneri larvae recording their position every 15 days. That it has done for a period of more than 100 years (1901-2010. The period (1901

  18. Larval cannibalism and pupal defense against cannibalism in two species of tenebrionid beetles.

    Science.gov (United States)

    Ichikawa, Toshio; Kurauchi, Toshiaki

    2009-08-01

    Cannibalism of pupae by larvae has been documented In many species of Insects, but the features of larval cannibalism and pupal defensive mechanisms against larval cannibalism have been largely Ignored. Pupae of tenebrionld beetles rotate their abdominal segments in a circular motion in response to the tactile stimulation of appendages, including legs, antennae, maxillary pulps, and wings. When the pupal abdominal rotation responses of Tenebrio molitor and Zophobas atratus were completely blocked by transecting the ventral nerve cord (VNC) of the pupae, the appendages of the paralytic pupae became initial, major targets for attack by larval cannibals. The majority of 20 paralytic pupae was cannibalized by 100 larvae within 6 h, and almost all the pupae were killed within 2-3 days. In contrast, only a few pupae of Z. atratus and several pupae of T. molitor were cannibalized when the VNC was Intact. The abdominal rotation response of the pupae thus functions as an effective defense against larval cannibalism.

  19. Strengthened currents override the effect of warming on lobster larval dispersal and survival

    NARCIS (Netherlands)

    Cetina-Heredia, Paulina; Roughan, Moninya; van Sebille, Erik|info:eu-repo/dai/nl/304831921; Feng, Ming; Coleman, Melinda A.

    2015-01-01

    Human-induced climate change is projected to increase ocean temperature and modify circulation patterns, with potential widespread implications for the transport and survival of planktonic larvae of marine organisms. Circulation affects the dispersal of larvae, whereas temperature impacts larval

  20. Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

    Science.gov (United States)

    Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

  1. Anomalies of larval and juvenile shortnose and lost river suckers in upper Klamath Lake, Oregon

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Larval and juvenile shortnose (Chasmistes brevirostris) and Lost River (Deltistes luxatus) suckers from Upper Klamath Lake, OR, were examined to determine anomaly...

  2. Temperature control of larval dispersal and the implications for marine ecology, evolution, and conservation.

    Science.gov (United States)

    O'Connor, Mary I; Bruno, John F; Gaines, Steven D; Halpern, Benjamin S; Lester, Sarah E; Kinlan, Brian P; Weiss, Jack M

    2007-01-23

    Temperature controls the rate of fundamental biochemical processes and thereby regulates organismal attributes including development rate and survival. The increase in metabolic rate with temperature explains substantial among-species variation in life-history traits, population dynamics, and ecosystem processes. Temperature can also cause variability in metabolic rate within species. Here, we compare the effect of temperature on a key component of marine life cycles among a geographically and taxonomically diverse group of marine fish and invertebrates. Although innumerable lab studies document the negative effect of temperature on larval development time, little is known about the generality versus taxon-dependence of this relationship. We present a unified, parameterized model for the temperature dependence of larval development in marine animals. Because the duration of the larval period is known to influence larval dispersal distance and survival, changes in ocean temperature could have a direct and predictable influence on population connectivity, community structure, and regional-to-global scale patterns of biodiversity.

  3. A High-Throughput Method for the Analysis of Larval Developmental Phenotypes in Caenorhabditis elegans.

    Science.gov (United States)

    Olmedo, María; Geibel, Mirjam; Artal-Sanz, Marta; Merrow, Martha

    2015-10-01

    Caenorhabditis elegans postembryonic development consists of four discrete larval stages separated by molts. Typically, the speed of progression through these larval stages is investigated by visual inspection of the molting process. Here, we describe an automated method to monitor the timing of these discrete phases of C. elegans maturation, from the first larval stage through adulthood, using bioluminescence. The method was validated with a lin-42 mutant strain that shows delayed development relative to wild-type animals and with a daf-2 mutant that shows an extended second larval stage. This new method is inherently high-throughput and will finally allow dissecting the molecular machinery governing the speed of the developmental clock, which has so far been hampered by the lack of a method suitable for genetic screens.

  4. AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

  5. Relevance of biofilm bacteria in modulating the larval metamorphosis of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Raghukumar, S.

    Balanus amphitrite, on its larval metamorphosis. The effect of multispecies bacterial film was also assessed. The production of different molecules by the bacteria was influenced by the nutrient media under which they were grown. It was observed...

  6. Measuring larval nematode contamination on cattle pastures: Comparing two herbage sampling methods.

    Science.gov (United States)

    Verschave, S H; Levecke, B; Duchateau, L; Vercruysse, J; Charlier, J

    2015-06-15

    Assessing levels of pasture larval contamination is frequently used to study the population dynamics of the free-living stages of parasitic nematodes of livestock. Direct quantification of infective larvae (L3) on herbage is the most applied method to measure pasture larval contamination. However, herbage collection remains labour intensive and there is a lack of studies addressing the variation induced by the sampling method and the required sample size. The aim of this study was (1) to compare two different sampling methods in terms of pasture larval count results and time required to sample, (2) to assess the amount of variation in larval counts at the level of sample plot, pasture and season, respectively and (3) to calculate the required sample size to assess pasture larval contamination with a predefined precision using random plots across pasture. Eight young stock pastures of different commercial dairy herds were sampled in three consecutive seasons during the grazing season (spring, summer and autumn). On each pasture, herbage samples were collected through both a double-crossed W-transect with samples taken every 10 steps (method 1) and four random located plots of 0.16 m(2) with collection of all herbage within the plot (method 2). The average (± standard deviation (SD)) pasture larval contamination using sampling methods 1 and 2 was 325 (± 479) and 305 (± 444)L3/kg dry herbage (DH), respectively. Large discrepancies in pasture larval counts of the same pasture and season were often seen between methods, but no significant difference (P = 0.38) in larval counts between methods was found. Less time was required to collect samples with method 2. This difference in collection time between methods was most pronounced for pastures with a surface area larger than 1 ha. The variation in pasture larval counts from samples generated by random plot sampling was mainly due to the repeated measurements on the same pasture in the same season (residual variance

  7. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan

    2011-07-29

    Background: The barnacle Balanus amphitrite is a globally distributed biofouler and a model species in intertidal ecology and larval settlement studies. However, a lack of genomic information has hindered the comprehensive elucidation of the molecular mechanisms coordinating its larval settlement. The pyrosequencing-based transcriptomic approach is thought to be useful to identify key molecular changes during larval settlement. Methodology and Principal Findings: Using 454 pyrosequencing, we collected totally 630,845 reads including 215,308 from the larval stages and 415,537 from the adults; 23,451 contigs were generated while 77,785 remained as singletons. We annotated 31,720 of the 92,322 predicted open reading frames, which matched hits in the NCBI NR database, and identified 7,954 putative genes that were differentially expressed between the larval and adult stages. Of these, several genes were further characterized with quantitative real-time PCR and in situ hybridization, revealing some key findings: 1) vitellogenin was uniquely expressed in late nauplius stage, suggesting it may be an energy source for the subsequent non-feeding cyprid stage; 2) the locations of mannose receptors suggested they may be involved in the sensory system of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval settlement. Conclusions: Our results provide not only the basis of several new hypotheses about gene functions during larval settlement, but also the availability of this large transcriptome dataset in B. amphitrite for further exploration of larval settlement and developmental pathways in this important marine species. © 2011 Chen et al.

  8. Hatching and larval export of the intertidal crab Neohelice granulata in Mar Chiquita coastal lagoon, Argentina

    OpenAIRE

    Guillermina Sánchez Vuichard; Nahuel Farías; Tomás Luppi

    2013-01-01

    Synchronization in the events of the reproductive cycle in female Neohelice granulata Dana, 1851 were studied from samples taken weekly and biweekly from September to December 2006 in the Laguna Mar Chiquita. The timing and larval hatching and synchronicity were inferred from numbers of ovigerous females and observing the stages of embryonic development. Synchronization in larval hatching also was observed in females in experiments in dark for a period of 48 hours, at three different saliniti...

  9. Functional evolution of Ets in echinoderms with focus on the evolution of echinoderm larval skeletons.

    Science.gov (United States)

    Koga, Hiroyuki; Matsubara, Mioko; Fujitani, Haruka; Miyamoto, Norio; Komatsu, Miéko; Kiyomoto, Masato; Akasaka, Koji; Wada, Hiroshi

    2010-09-01

    Convergent evolution of echinoderm pluteus larva was examined from the standpoint of functional evolution of a transcription factor Ets1/2. In sea urchins, Ets1/2 plays a central role in the differentiation of larval skeletogenic mesenchyme cells. In addition, Ets1/2 is suggested to be involved in adult skeletogenesis. Conversely, in starfish, although no skeletogenic cells differentiate during larval development, Ets1/2 is also expressed in the larval mesoderm. Here, we confirmed that the starfish Ets1/2 is indispensable for the differentiation of the larval mesoderm. This result led us to assume that, in the common ancestors of echinoderms, Ets1/2 activates the transcription of distinct gene sets, one for the differentiation of the larval mesoderm and the other for the development of the adult skeleton. Thus, the acquisition of the larval skeleton involved target switching of Ets1/2. Specifically, in the sea urchin lineage, Ets1/2 activated a downstream target gene set for skeletogenesis during larval development in addition to a mesoderm target set. We examined whether this heterochronic activation of the skeletogenic target set was achieved by the molecular evolution of the Ets1/2 transcription factor itself. We tested whether starfish Ets1/2 induced skeletogenesis when injected into sea urchin eggs. We found that, in addition to ectopic induction of mesenchyme cells, starfish Ets1/2 can activate some parts of the skeletogenic pathway in these mesenchyme cells. Thus, we suggest that the nature of the transcription factor Ets1/2 did not change, but rather that some unidentified co-factor(s) for Ets1/2 may distinguish between targets for the larval mesoderm and for skeletogenesis. Identification of the co-factor(s) will be key to understanding the molecular evolution underlying the evolution of the pluteus larvae.

  10. The influence of larval competition on Brazilian Wolbachia-infected Aedes aegypti mosquitoes.

    Science.gov (United States)

    Dutra, Heverton Leandro Carneiro; Lopes da Silva, Vanessa; da Rocha Fernandes, Mariana; Logullo, Carlos; Maciel-de-Freitas, Rafael; Moreira, Luciano Andrade

    2016-05-16

    With field releases starting in Brazil, particular interest must be given to understanding how the endosymbiotic bacterium Wolbachia pipientis affects Aedes aegypti mosquitoes with a Brazilian genetic background. Currently, there is limited information on how the bacterium affects phenotypic traits such as larval development rate, metabolic reserves and morphometric parameters in Ae. aegypti. Here, we analyze for the first time, the effect of Wolbachia on these key phenotypes and consider how this might impact the potential of the bacterium as a disease control agent in Brazil. We examined the influence of the wMel strain of Wolbachia in laboratory Ae. aegypti with a Brazilian genetic background, reared under different larval densities. Pupae formation was counted daily to assess differences in development rates. Levels of metabolic reserves and morphometric parameters were assessed in adults resulting from each larval condition. wMel infection led to more rapid larval development at higher densities for both males and females, with no effect under less crowded conditions in females. Infection also led to reduced body size at both high and low density, but not at intermediate density, although the scale of this difference was maintained regardless of larval density, in comparison to uninfected individuals. Wing shape also varied significantly between infected and uninfected mosquitoes due to larval density. Glycogen levels in uninfected mosquitoes decreased under higher larval density, but were consistently high with Wolbachia infection, regardless of larval density. We demonstrate that the wMel Wolbachia strain can positively influence some important host fitness traits, and that this interaction is directly linked to the conditions in which the host is reared. Combined with previously published data, these results suggest that this Wolbachia strain could be successfully used as part of the Eliminate Dengue Program in Brazil.

  11. Exposure to 2,4-decadienal negatively impacts upon marine invertebrate larval fitness.

    Science.gov (United States)

    Caldwell, Gary S; Lewis, Ceri; Olive, Peter J W; Bentley, Matthew G

    2005-06-01

    Diatoms liberate volatile, biologically active unsaturated aldehydes following cell damage, which negatively impact upon invertebrate reproductive processes such as fertilization, embryogenesis and larval survival. 2,4-Decadienal is frequently identified among the aldehydes produced and is one of the more biologically active. The majority of studies which have examined the toxic effects of diatom aldehydes to invertebrate reproduction have scored egg production and/or hatching success as indicators of biological impacts. There are very few studies which have dealt specifically with the impacts of diatom-derived aldehydes on larval fitness. Larval stages of the polychaetes Arenicola marina and Nereis virens and the echinoderms Asterias rubens and Psammechinus miliaris exposed to 2,4-decadienal at sub 1 microg ml(-1) concentrations suffered reduced survival over the incubation period (day 1-8 post fertilization) with detectable differences for the polychates at a concentration of 0.005 and 0.01-0.1 microg ml(-1) for the echinoderms. Susceptibility of larval N. virens was investigated using stage specific 24 h exposures at 2,4-decadienal concentrations up to 1.5 microg ml(-1). A clear stage specific effect was found, with earlier larval stages most vulnerable. Nectochaete larvae (9-10 d) showed no reduction in survival at the concentrations assayed. Fluctuating asymmetry (FA), defined as random deviations from perfect bilateral symmetry, was used to analyse fitness of larval P. miliaris exposed to 2,4-decadienal at concentrations of 0.1, 0.5 and 1 microg ml(-1). The degree and frequency of asymmetrical development increased with increasing 2,4-decadienal concentration. Equally, as FA increased larval survival decreased. These results provide further support for the teratogenic nature of 2,4-decadienal and its negative impact on invertebrate larval fitness.

  12. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    Takken Willem

    2010-01-01

    Full Text Available Abstract Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density, fungus (species and concentration and environmental effects (exposure duration and food availability influence larval mortality caused by fungus, was studied. Methods Laboratory bioassays were performed on the larval stages of Anopheles gambiae and Anopheles stephensi with spores of two fungus species, Metarhizium anisopliae and Beauveria bassiana. For various larval and fungal characteristics and environmental effects the time to death was determined and survival curves established. These curves were compared by Kaplan Meier and Cox regression analyses. Results Beauveria bassiana and Metarhizium anisopliae caused high mortality of An. gambiae and An. stephensi larvae. However, Beauveria bassiana was less effective (Hazard ratio (HR Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR Conclusions This study shows that both fungus species have potential to kill mosquitoes in the larval stage, and that mortality rate depends on fungus species itself, larval stage targeted, larval density and amount of nutrients available to the larvae. Increasing the concentration of fungal spores or reducing the exposure time to spores did not show a proportional increase and decrease in mortality rate, respectively, because the spores clumped together. As a result spores did not provide uniform coverage over space and time. It is, therefore, necessary to develop a formulation that allows the spores to spread over the water surface. Apart from formulation appropriate delivery methods are also necessary to avoid exposing non-target organisms to fungus.

  13. Replenishment success linked to fluctuating asymmetry in larval fish.

    Science.gov (United States)

    Lemberget, Tove; McCormick, Mark I

    2009-02-01

    Fluctuating asymmetry (FA), defined as random deviations from perfect symmetry, has become a popular tool with which to examine the effects of stress during the development of bilaterally symmetrical organisms. Recent studies have suggested that FA in otoliths may serve as an indicator of stress in fish larvae. We examined the relationship between otolith asymmetry and temporal patterns in the occurrence of late-stage larvae to a tropical reef (i.e. replenishment) for the Caribbean lizardfish, Saurida suspicio (family Synodontidae). Late-stage larvae were collected in light traps over a period of 18 consecutive lunar months in the San Blas Archipelago, Panama. Asymmetry within otolith pairs was calculated from 24 variables: area, perimeter, longest and shortest axis of the otolith and 20 shape descriptors (Fourier harmonics). Otolith asymmetry was correlated strongly with fluctuations in lunar light trap catches. Two measured variables, otolith area and one of the 20 shape descriptors, accounted for 60% of the variability in lunar replenishment of S. suspicio. Individuals from small replenishment pulses exhibited higher levels of asymmetry compared to larvae from large pulses. When dry and wet seasons were analysed separately, otolith asymmetry explained a surprising 70 and 97% of the variation, respectively. Although the generality of these results remain to be tested among other populations and species, otolith asymmetry may be an important indicator, and potentially a predictor, of larval quality and replenishment success.

  14. Positive effects of nonnative invasive Phragmites australis on larval bullfrogs.

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    Mary Alta Rogalski

    Full Text Available BACKGROUND: Nonnative Phragmites australis (common reed is one of the most intensively researched and managed invasive plant species in the United States, yet as with many invasive species, our ability to predict, control or understand the consequences of invasions is limited. Rapid spread of dense Phragmites monocultures has prompted efforts to limit its expansion and remove existing stands. Motivation for large-scale Phragmites eradication programs includes purported negative impacts on native wildlife, a view based primarily on observational results. We took an experimental approach to test this assumption, estimating the effects of nonnative Phragmites australis on a native amphibian. METHODOLOGY/PRINCIPAL FINDINGS: Concurrent common garden and reciprocal transplant field experiments revealed consistently strong positive influences of Phragmites on Rana catesbeiana (North American bullfrog larval performance. Decomposing Phragmites litter appears to contribute to the effect. CONCLUSIONS/SIGNIFICANCE: Positive effects of Phragmites merit further research, particularly in regions where both Phragmites and R. catesbeiana are invasive. More broadly, the findings of this study reinforce the importance of experimental evaluations of the effects of biological invasion to make informed conservation and restoration decisions.

  15. Structural study of the frog Rana temporaria larval stomach.

    Science.gov (United States)

    Rovira, J; Villaro, A C; Bodegas, M E; Valverde, E; Sesma, P

    1993-10-01

    The gastric wall of Rana temporaria tadpoles consists of a well-developed mucosa and thin muscular and serosa layers. Three cellular types--mucous, ciliated and endocrine cells--make up the lining epithelium. Different types of endocrine cells exist. Argyrophylic endocrine cells can be recognized in semithin sections of plastic-embedded material while non-argyrophylic endocrine cells can only be identified under the electron microscope. Glands are composed mainly of well-differentiated oxyntic cells and, occasionally, scarce endocrine cells. Oxyntic cells show abundant mitochondria and smooth endoplasmic reticulum, but do not contain zymogen granules as do those present in adults. Secretory canaliculi with microvilli are also well-developed. The lamina propria contains numerous vascular sinuses and nerve bundles which innervate the endothelium and some endocrine cells. The neuroendocrine regulation of frog gastric functions seems therefore to have developed in young tadpoles. Nerve fibers also innervate the muscular propria, which is composed of a single layer of smooth muscle cells. Underlying the muscle, connective fibers and a flattened layer of mesothelial cells make up the serosa. In summary, the structure of the frog larval stomach shows a well-differentiated histological pattern, especially referring to surface epithelium and glands. Some of the histological traits will also be present in adult frogs while others are characteristic of the tadpole's stage.

  16. Distribution of ferric iron in larval lampreys, Petromyzon marinus L.

    Science.gov (United States)

    Hall, S J; Youson, J H

    1988-01-01

    The distribution and abundance of ferric iron in larval lampreys (Petromyzon marinus L.) were investigated using light microscopy and the Prussian blue stain. Animals from various watersheds contained different concentrations of iron, although the sites of deposition were the same for all animals. A major portion of iron is within adipose tissue, while the liver, and cartilage contain predominantly low to trace amounts of iron, respectively. Iron is associated with fibrous connective tissue in several places in the body, and this association may have particular significance in the inner ear. Iron is also located in cells of the meninges. The presence of iron in the epithelial cells of the posterior intestine may reflect elimination of the metal through the extrusion of iron-loaded cells into the intestinal lumen. Iron within mucous cells of the epidermis, suggest elimination of iron during mucous secretion. Iron-loaded cells of bipolar shape are also present in the epidermis, but are particularly prominent around the branchiopore. Low concentrations of iron are observed within in melanin-containing macrophages (melano-macrophages) in regions of iron absorption, erythrophagocytosis, and haemopoiesis. High levels of iron in the epithelia and lumina of pronephric tubules are concomitant with degeneration of this organ. These data are evidence of the wide spread distribution of iron in lamprey tissues and additional evidence for the potential value of lampreys for the study of iron metabolism in vertebrates.

  17. Connectivity dominates larval replenishment in a coastal reef fish metapopulation.

    Science.gov (United States)

    Saenz-Agudelo, Pablo; Jones, Geoffrey P; Thorrold, Simon R; Planes, Serge

    2011-10-07

    Direct estimates of larval retention and connectivity are essential to understand the structure and dynamics of marine metapopulations, and optimize the size and spacing of reserves within networks of marine-protected areas (MPAs). For coral reef fishes, while there are some empirical estimates of self-recruitment at isolated populations, exchange among sub-populations has been rarely quantified. Here, we used microsatellite DNA markers and a likelihood-based parentage analysis to assess the relative magnitude of self-recruitment and exchange among eight geographically distinct sub-populations of the panda clownfish Amphiprion polymnus along 30 km of coastline near Port Moresby, Papua New Guinea. In addition, we used an assignment/exclusion test to identify immigrants arriving from genetically distinct sources. Overall, 82 per cent of the juveniles were immigrants while 18 per cent were progeny of parents genotyped in our focal metapopulation. Of the immigrants, only 6 per cent were likely to be genetically distinct from the focal metapopulation, suggesting most of the connectivity is among sub-populations from a rather homogeneous genetic pool. Of the 18 per cent that were progeny of known adults, two-thirds dispersed among the eight sub-populations and only one-third settled back into natal sub-populations. Comparison of our data with previous studies suggested that variation in dispersal distances is likely to be influenced by the geographical setting and spacing of sub-populations.

  18. Preference for and learning of amino acids in larval Drosophila

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    Nana Kudow

    2017-03-01

    Full Text Available Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.

  19. Preference for and learning of amino acids in larval Drosophila.

    Science.gov (United States)

    Kudow, Nana; Miura, Daisuke; Schleyer, Michael; Toshima, Naoko; Gerber, Bertram; Tanimura, Teiichi

    2017-03-15

    Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis - and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.

  20. Cannibalistic feeding of larval Trichogramma carverae parasitoids in moth eggs

    Science.gov (United States)

    Heslin, Leeane M.; Merritt, David J.

    2005-09-01

    Wasps of the genus Trichogramma parasitise the eggs of Lepidoptera. They may deposit one or many eggs in each host. Survival is high at low density but reaches a plateau as density increases. To reveal the mechanism by which excess larvae die we chose a lepidopteran host that has flattened, transparent eggs and used video microscopy to record novel feeding behaviours and interactions of larval Trichogramma carverae (Oatman and Pinto) at different densities. Single larvae show a rapid food ingestion phase, followed by a period of extensive saliva release. Ultimately the host egg is completely consumed. The larva then extracts excess moisture from the egg, providing a dry environment for pupation. When multiple larvae are present, the initial scramble for food results in the larvae consuming all of the egg contents early in development. All larvae survive if there is sufficient food for all to reach a threshold developmental stage. If not, physical proximity results in attack and consumption of others, continuing until the surviving larvae reach the threshold stage beyond which attacks seem to be no longer effective. The number of larvae remaining at the end of rapid ingestion dictates how many will survive to emerge as adults.

  1. Research Advances in Human and Mammalian Semen Proteomic%人和哺乳动物精液的蛋白质组学研究进展

    Institute of Scientific and Technical Information of China (English)

    杨丽; 付强; 薛雯; 张明

    2012-01-01

    蛋白质组学技术是21世纪研究生命科学最有价值的技术之一,将其应用到精子和精浆蛋白质的研究后,已取得了许多成果.对蛋白质组、蛋白质组学、双向电泳、质谱、生物信息学等进行了简要介绍,并重点阐述了蛋白质组学技术在精子蛋白和精浆蛋白上的研究进展.%[Objective]The research aimed to optimize laboratory artificial rearing methods for Plutella xylostella L. and to select out effective insecticides against this pest species.[Method]Brassica chinensis seedlings were cultivated in the laboratory at (25 ±1 )℃ , 60 -75% RH, and a photoperiod of 14:10 ( L:D) h. The green blow molding papers were used to collect eggs, and Brassica oleracea seedlings were cultivated to breed Plutella xylostella L. until the insects were ready for use. Meanwhile, the susceptibility of 3rd instar larvae of Plutella xylostella L. to five types of insecticides was tested by leaf-dipping method. [Result]Plutella xylostella L. larvae were found well-grown and uniform in devel opmental stages with average pupa weight of 5.4 mg, pupa emergence percentage of 94.0 % and egg number of 135. 1 per female. The LC50, values of 3rd instar Plutella xylostella L. larvae against 200 g/L chlorantraniliprole SC, 20% flubendiamide WG, 150 g/L indoxacarb EC, 200 g/L tebufenozide SC and 1.8% abamectinEC, were 0.152, 0.223, 1.151, 93.340 and 0. 128 mg/L, respectively. [Conclusion]This rearing method is easy to be implemented and of great practicality, suitable for mass propagation of P. xylostella L. Abamectin, chlorantranil iprole and flubendiamide showed high insecticidal activities, so these three insecticides can be used alternately for the field prevention and con trol of Plutella xylostella L.

  2. Relative impacts of adult movement, larval dispersal and harvester movement on the effectiveness of reserve networks.

    Science.gov (United States)

    Grüss, Arnaud; Kaplan, David M; Hart, Deborah R

    2011-01-01

    Movement of individuals is a critical factor determining the effectiveness of reserve networks. Marine reserves have historically been used for the management of species that are sedentary as adults, and, therefore, larval dispersal has been a major focus of marine-reserve research. The push to use marine reserves for managing pelagic and demersal species poses significant questions regarding their utility for highly-mobile species. Here, a simple conceptual metapopulation model is developed to provide a rigorous comparison of the functioning of reserve networks for populations with different admixtures of larval dispersal and adult movement in a home range. We find that adult movement produces significantly lower persistence than larval dispersal, all other factors being equal. Furthermore, redistribution of harvest effort previously in reserves to remaining fished areas ('fishery squeeze') and fishing along reserve borders ('fishing-the-line') considerably reduce persistence and harvests for populations mobile as adults, while they only marginally changes results for populations with dispersing larvae. Our results also indicate that adult home-range movement and larval dispersal are not simply additive processes, but rather that populations possessing both modes of movement have lower persistence than equivalent populations having the same amount of 'total movement' (sum of larval and adult movement spatial scales) in either larval dispersal or adult movement alone.

  3. Larval density dependence in Anopheles gambiae s.s., the major African vector of malaria

    Science.gov (United States)

    Muriu, Simon M.; Coulson, Tim; Mbogo, Charles M.; Godfray, H. Charles J.

    2017-01-01

    Summary Anopheles gambiae sensu stricto is the most important vector of malaria in Africa although relatively little is known about the density-dependent processes determining its population size.Mosquito larval density was manipulated under semi-natural conditions using artificial larval breeding sites placed in the field in coastal Kenya; two experiments were conducted: one manipulating the density of a single cohort of larvae across a range of densities and the other employing fewer densities but with the treatments crossed with four treatments manipulating predator access.In the first experiment, larval survival, development rate and the size of the adult mosquito all decreased with larval density (controlling for block effects between 23% and 31% of the variance in the data could be explained by density).In the second experiment, the effects of predator manipulation were not significant, but again we observed strong density dependence in larval survival (explaining 30% of the variance).The results are compared with laboratory studies of A. gambiae larval competition and the few other studies conducted in the field, and the consequences for malaria control are discussed PMID:23163565

  4. The role of internal waves in larval fish interactions with potential predators and prey

    Science.gov (United States)

    Greer, Adam T.; Cowen, Robert K.; Guigand, Cedric M.; Hare, Jonathan A.; Tang, Dorothy

    2014-09-01

    Tidally driven internal wave packets in coastal environments have the potential to influence patchiness of larval fishes, prey, and gelatinous predators. We used the In Situ Ichthyoplankton Imaging System (ISIIS) to synoptically sample larval fishes, copepods, and planktonic predators (ctenophores, hydromedusae, chaetognaths, and polychaetes) across these predictable features in the summer near Stellwagen Bank, Massachusetts, USA. Full water column profiles and fixed depth transects (∼10 m depth) were used to quantify vertical and horizontal components of the fish and invertebrate distributions during stable and vertically mixed conditions associated with tidally generated internal waves. Larval fishes, consisting mostly of Urophycis spp., Merluccius bilinearis, and Labridae, were concentrated near the surface, with larger sizes generally occupying greater depths. During stable water column conditions, copepods formed a near surface thin layer several meters above the chlorophyll-a maximum that was absent when internal waves were propagating. In contrast, ctenophores and other predators were much more abundant at depth, but concentrations near 10 m increased immediately after the internal hydraulic jump mixed the water column. During the propagation of internal waves, the fine-scale abundance of larval fishes was more correlated with the abundance of gelatinous predators and less correlated with copepods compared to the stable conditions. Vertical oscillations caused by the internal hydraulic jump can disperse patches of zooplankton and force surface dwelling larval fishes into deeper water where probability of predator contact is increased, creating conditions potentially less favorable for larval fish growth and survival on short time scales.

  5. Drosophila Food-Associated Pheromones: Effect of Experience, Genotype and Antibiotics on Larval Behavior.

    Science.gov (United States)

    Thibert, Julien; Farine, Jean-Pierre; Cortot, Jérôme; Ferveur, Jean-François

    2016-01-01

    Animals ubiquitously use chemical signals to communicate many aspects of their social life. These chemical signals often consist of environmental cues mixed with species-specific signals-pheromones-emitted by conspecifics. During their life, insects can use pheromones to aggregate, disperse, choose a mate, or find the most suitable food source on which to lay eggs. Before pupariation, larvae of several Drosophila species migrate to food sources depending on their composition and the presence of pheromones. Some pheromones derive from microbiota gut activity and these food-associated cues can enhance larval attraction or repulsion. To explore the mechanisms underlying the preference (attraction/repulsion) to these cues and clarify their effect, we manipulated factors potentially involved in larval response. In particular, we found that the (i) early exposure to conspecifics, (ii) genotype, and (iii) antibiotic treatment changed D. melanogaster larval behavior. Generally, larvae-tested either individually or in groups-strongly avoided food processed by other larvae. Compared to previous reports on larval attractive pheromones, our data suggest that such attractive effects are largely masked by food-associated compounds eliciting larval aversion. The antagonistic effect of attractive vs. aversive compounds could modulate larval choice of a pupariation site and impact the dispersion of individuals in nature.

  6. Relative impacts of adult movement, larval dispersal and harvester movement on the effectiveness of reserve networks.

    Directory of Open Access Journals (Sweden)

    Arnaud Grüss

    Full Text Available Movement of individuals is a critical factor determining the effectiveness of reserve networks. Marine reserves have historically been used for the management of species that are sedentary as adults, and, therefore, larval dispersal has been a major focus of marine-reserve research. The push to use marine reserves for managing pelagic and demersal species poses significant questions regarding their utility for highly-mobile species. Here, a simple conceptual metapopulation model is developed to provide a rigorous comparison of the functioning of reserve networks for populations with different admixtures of larval dispersal and adult movement in a home range. We find that adult movement produces significantly lower persistence than larval dispersal, all other factors being equal. Furthermore, redistribution of harvest effort previously in reserves to remaining fished areas ('fishery squeeze' and fishing along reserve borders ('fishing-the-line' considerably reduce persistence and harvests for populations mobile as adults, while they only marginally changes results for populations with dispersing larvae. Our results also indicate that adult home-range movement and larval dispersal are not simply additive processes, but rather that populations possessing both modes of movement have lower persistence than equivalent populations having the same amount of 'total movement' (sum of larval and adult movement spatial scales in either larval dispersal or adult movement alone.

  7. Enhancement of larval RNAi efficiency by over-expressing Argonaute2 in Bombyx mori.

    Science.gov (United States)

    Li, Zhiqian; Zeng, Baosheng; Ling, Lin; Xu, Jun; You, Lang; Aslam, Abu F M; Tan, Anjiang; Huang, Yongping

    2015-01-01

    RNA interference has been described as a powerful genetic tool for gene functional analysis and a promising approach for pest management. However, RNAi efficiency varies significantly among insect species due to distinct RNAi machineries. Lepidopteran insects include a large number of pests as well as model insects, such as the silkworm, Bombyx mori. However, only limited success of in vivo RNAi has been reported in lepidoptera, particularly during the larval stages when the worms feed the most and do the most harm to the host plant. Enhancing the efficiency of larval RNAi in lepidoptera is urgently needed to develop RNAi-based pest management strategies. In the present study, we investigate the function of the conserved RNAi core factor, Argonaute2 (Ago2), in mediating B. mori RNAi efficiency. We demonstrate that introducing BmAgo2 dsRNA inhibits the RNAi response in both BmN cells and embryos. Furthermore, we establish several transgenic silkworm lines to assess the roles of BmAgo2 in larval RNAi. Over-expressing BmAgo2 significantly facilitated both dsRNA-mediated larval RNAi when targeting DsRed using dsRNA injection and shRNA-mediated larval RNAi when targeting BmBlos2 using transgenic shRNA expression. Our results show that BmAgo2 is involved in RNAi in B. mori and provides a promising approach for improving larval RNAi efficiency in B. mori and in lepidopteran insects in general.

  8. Shifty salamanders: transient trophic polymorphism and cannibalism within natural populations of larval ambystomatid salamanders.

    Science.gov (United States)

    Jefferson, Dale M; Ferrari, Maud Co; Mathis, Alicia; Hobson, Keith A; Britzke, Eric R; Crane, Adam L; Blaustein, Andrew R; Chivers, Douglas P

    2014-01-01

    Many species of ambystomatid salamanders are dependent upon highly variable temporary wetlands for larval development. High larval densities may prompt the expression of a distinct head morphology that may facilitate cannibalism. However, few studies have characterized structural cannibalism within natural populations of larval salamanders. In this study we used two species of larval salamanders, long-toed (Ambystoma macrodactylum) and ringed salamanders (A. annulatum). Head morphometrics and stable isotopic values of carbon (δ(13)C) and nitrogen (δ(15)N) were used to identify the presence or absence of structural cannibalism. Weather conditions were also analyzed as a potential factor associated with the expression of cannibalistic morphology. Populations of salamander larvae did not consistently exhibit cannibalistic morphologies throughout collection periods. Larval long-toed salamanders exhibited trophic polymorphisms when relatively lower precipitation amounts were observed. Larval ringed salamanders were observed to be cannibalistic but did not exhibit polymorphisms in this study. Structural cannibalism may be transient in both species; however in long-toed salamanders this morphology is necessary for cannibalism. Ringed salamanders can be cannibalistic without morphological adaptations; however the cannibal morph may prolong the viable time period for cannibalism. Additionally, weather conditions may alter pond hydroperiod, subsequently influencing head morphology and cannibalism.

  9. Larval connectivity of pearl oyster through biophysical modelling; evidence of food limitation and broodstock effect

    Science.gov (United States)

    Thomas, Yoann; Dumas, Franck; Andréfouët, Serge

    2016-12-01

    The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia atoll lagoons. This aquaculture relies on spat collection, a process that experiences spatial and temporal variability and needs to be optimized by understanding which factors influence recruitment. Here, we investigate the sensitivity of P. margaritifera larval dispersal to both physical and biological factors in the lagoon of Ahe atoll. Coupling a validated 3D larval dispersal model, a bioenergetics larval growth model following the Dynamic Energy Budget (DEB) theory, and a population dynamics model, the variability of lagoon-scale connectivity patterns and recruitment potential is investigated. The relative contribution of reared and wild broodstock to the lagoon-scale recruitment potential is also investigated. Sensitivity analyses pointed out the major effect of the broodstock population structure as well as the sensitivity to larval mortality rate and inter-individual growth variability to larval supply and to the subsequent settlement potential. The application of the growth model clarifies how trophic conditions determine the larval supply and connectivity patterns. These results provide new cues to understand the dynamics of bottom-dwelling populations in atoll lagoons, their recruitment, and discuss how to take advantage of these findings and numerical models for pearl oyster management.

  10. Influence of generation and photoperiod on larval development of Lobesia botrana (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Pavan, Francesco; Floreani, Chiara; Barro, Paola; Zandigiacomo, Pietro; Montà, Laura Dalla

    2010-10-01

    The influence of generation (under field conditions) and photoperiod (under laboratory conditions) on Lobesia botrana larvae development was studied. Some larvae were collected during three annual generations in two grape-growing areas of northeastern Italy, and others were individually reared in the laboratory from egg to pupa on an artificial diet under two different photoperiod conditions (respectively, daylight 16 h/d [long day {LD}] and 14 h/d [short day {SD}]). The mandible lengths of collected larvae were measured and the data analyzed morphometrically to determine the number of larval instars. In the laboratory study, the number of larval moultings, the mandible length of each instar, the development time from hatching larva to pupa, and the pupal weight were considered. The measurement of mandible lengths of larvae collected in the field indicated the existence of five larval instars in all three annual generations, but the size of the two oldest larval instars was significantly higher for third-generation larvae than for the previous generations. Under laboratory conditions, the larvae usually exhibited five instars, but the mandible lengths of larvae and the pupa size were greater for individuals reared under SD. These also took a greater number of days to develop from hatching larvae to pupae. Because a larger size of the final larval instar occurs in individuals that produce diapausing pupae under SD in both the laboratory and the field, a positive association between larval size and the probability of surviving the winter can be inferred.

  11. Is the Schwabe Organ a Retained Larval Eye? Anatomical and Behavioural Studies of a Novel Sense Organ in Adult Leptochiton asellus (Mollusca, Polyplacophora Indicate Links to Larval Photoreceptors.

    Directory of Open Access Journals (Sweden)

    Lauren H Sumner-Rooney

    Full Text Available The discovery of a sensory organ, the Schwabe organ, was recently reported as a unifying feature of chitons in the order Lepidopleurida. It is a patch of pigmented tissue located on the roof of the pallial cavity, beneath the velum on either side of the mouth. The epithelium is densely innervated and contains two types of potential sensory cells. As the function of the Schwabe organ remains unknown, we have taken a cross-disciplinary approach, using anatomical, histological and behavioural techniques to understand it. In general, the pigmentation that characterises this sensory structure gradually fades after death; however, one particular concentrated pigment dot persists. This dot is positionally homologous to the larval eye in chiton trochophores, found in the same neuroanatomical location, and furthermore the metamorphic migration of the larval eye is ventral in species known to possess Schwabe organs. Here we report the presence of a discrete subsurface epithelial structure in the region of the Schwabe organ in Leptochiton asellus that histologically resembles the chiton larval eye. Behavioural experiments demonstrate that Leptochiton asellus with intact Schwabe organs actively avoid an upwelling light source, while Leptochiton asellus with surgically ablated Schwabe organs and a control species lacking the organ (members of the other extant order, Chitonida do not (Kruskal-Wallis, H = 24.82, df = 3, p < 0.0001. We propose that the Schwabe organ represents the adult expression of the chiton larval eye, being retained and elaborated in adult lepidopleurans.

  12. Is the Schwabe Organ a Retained Larval Eye? Anatomical and Behavioural Studies of a Novel Sense Organ in Adult Leptochiton asellus (Mollusca, Polyplacophora) Indicate Links to Larval Photoreceptors.

    Science.gov (United States)

    Sumner-Rooney, Lauren H; Sigwart, Julia D

    2015-01-01

    The discovery of a sensory organ, the Schwabe organ, was recently reported as a unifying feature of chitons in the order Lepidopleurida. It is a patch of pigmented tissue located on the roof of the pallial cavity, beneath the velum on either side of the mouth. The epithelium is densely innervated and contains two types of potential sensory cells. As the function of the Schwabe organ remains unknown, we have taken a cross-disciplinary approach, using anatomical, histological and behavioural techniques to understand it. In general, the pigmentation that characterises this sensory structure gradually fades after death; however, one particular concentrated pigment dot persists. This dot is positionally homologous to the larval eye in chiton trochophores, found in the same neuroanatomical location, and furthermore the metamorphic migration of the larval eye is ventral in species known to possess Schwabe organs. Here we report the presence of a discrete subsurface epithelial structure in the region of the Schwabe organ in Leptochiton asellus that histologically resembles the chiton larval eye. Behavioural experiments demonstrate that Leptochiton asellus with intact Schwabe organs actively avoid an upwelling light source, while Leptochiton asellus with surgically ablated Schwabe organs and a control species lacking the organ (members of the other extant order, Chitonida) do not (Kruskal-Wallis, H = 24.82, df = 3, p organ represents the adult expression of the chiton larval eye, being retained and elaborated in adult lepidopleurans.

  13. Intrinsic properties of larval zebrafish neurons in ethanol.

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    Hiromi Ikeda

    Full Text Available The behavioral effects of ethanol have been studied in multiple animal models including zebrafish. Locomotion of zebrafish larvae is resistant to high concentrations of ethanol in bath solution. This resistance has been attributed to a lower systemic concentration of ethanol in zebrafish when compared with bath solution, although the mechanism to maintain such a steep gradient is unclear. Here we examined whether the intrinsic properties of neurons play roles in this resistance. In order to minimize the contribution of metabolism and diffusional barriers, larvae were hemisected and the anterior half immersed in a range of ethanol concentrations thereby ensuring the free access of bath ethanol to the brain. The response to vibrational stimuli of three types of reticulospinal neurons: Mauthner neurons, vestibulospinal neurons, and MiD3 neurons were examined using an intracellular calcium indicator. The intracellular [Ca(2+] response in MiD3 neurons decreased in 100 mM ethanol, while Mauthner neurons and vestibulospinal neurons required >300 mM ethanol to elicit similar effects. The ethanol effect in Mauthner neurons was reversible following removal of ethanol. Interestingly, activities of MiD3 neurons displayed spontaneous recovery in 300 mM ethanol, suggestive of acute tolerance. Finally, we examined with mechanical vibration the startle response of free-swimming larvae in 300 mM ethanol. Ethanol treatment abolished long latency startle responses, suggesting a functional change in neural processing. These data support the hypothesis that individual neurons in larval zebrafish brains have distinct patterns of response to ethanol dictated by specific molecular targets.

  14. Genetic analysis of Eclosion hormone action during Drosophila larval ecdysis.

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    Krüger, Eileen; Mena, Wilson; Lahr, Eleanor C; Johnson, Erik C; Ewer, John

    2015-12-15

    Insect growth is punctuated by molts, during which the animal produces a new exoskeleton. The molt culminates in ecdysis, an ordered sequence of behaviors that causes the old cuticle to be shed. This sequence is activated by Ecdysis triggering hormone (ETH), which acts on the CNS to activate neurons that produce neuropeptides implicated in ecdysis, including Eclosion hormone (EH), Crustacean cardioactive peptide (CCAP) and Bursicon. Despite more than 40 years of research on ecdysis, our understanding of the precise roles of these neurohormones remains rudimentary. Of particular interest is EH; although it is known to upregulate ETH release, other roles for EH have remained elusive. We isolated an Eh null mutant in Drosophila and used it to investigate the role of EH in larval ecdysis. We found that null mutant animals invariably died at around the time of ecdysis, revealing an essential role in its control. Further analyses showed that these animals failed to express the preparatory behavior of pre-ecdysis while directly expressing the motor program of ecdysis. Although ETH release could not be detected, the lack of pre-ecdysis could not be rescued by injections of ETH, suggesting that EH is required within the CNS for ETH to trigger the normal ecdysial sequence. Using a genetically encoded calcium probe, we showed that EH configured the response of the CNS to ETH. These findings show that EH plays an essential role in the Drosophila CNS in the control of ecdysis, in addition to its known role in the periphery of triggering ETH release.

  15. Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci

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    Alberto Guevara-Flores

    2010-01-01

    Full Text Available Mitochondrial thioredoxin-glutathione reductase was purified from larval Taenia crassiceps (cysticerci. The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At 25∘C specific activities were 437  ±  27 mU mg-1 and 840  ±  49 mU mg-1 with thioredoxin and GSSG, respectively. Apparent Km values were 0.87  ±  0.04  μM, 41  ±  6  μM and 19  ±  10  μM for thioredoxin, GSSG and NADPH, respectively. Thioredoxin from eukaryotic sources was accepted as substrate. The enzyme reduced H2O2 in a NADPH-dependent manner, although with low catalytic efficiency. In the presence of thioredoxin, mitochondrial TGR showed a thioredoxin peroxidase-like activity. All disulfide reductase activities were inhibited by auranofin, suggesting mTGR is dependent on selenocysteine. The reductase activity with GSSG showed a higher dependence on temperature as compared with the DTNB reductase activity. The variation of the GSSG- and DTNB reductase activities on pH was dependent on the disulfide substrate. Like the cytosolic isoform, mTGR showed a hysteretic kinetic behavior at moderate or high GSSG concentrations, but it was less sensitive to calcium. The enzyme was able to protect glutamine synthetase from oxidative inactivation, suggesting that mTGR is competent to contend with oxidative stress.

  16. Visual acuity in larval zebrafish: behavior and histology

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    Mueller Kaspar P

    2010-03-01

    Full Text Available Abstract Background Visual acuity, the ability of the visual system to distinguish two separate objects at a given angular distance, is influenced by the optical and neuronal properties of the visual system. Although many factors may contribute, the ultimate limit is photoreceptor spacing. In general, at least one unstimulated photoreceptor flanked by two stimulated ones is needed to perceive two objects as separate. This critical interval is also referred to as the Nyquist frequency and is according to the Shannon sampling theorem the highest spatial frequency where a pattern can be faithfully transmitted. We measured visual acuity in a behavioral experiment and compared the data to the physical limit given by photoreceptor spacing in zebrafish larvae. Results We determined visual acuity by using the optokinetic response (OKR, reflexive eye movements in response to whole field movements of the visual scene. By altering the spatial frequency we determined the visual acuity at approximately 0.16 cycles/degree (cpd (minimum separable angle = 3.1°. On histological sections we measured the retinal magnification factor and the distance between double cones, that are thought to mediate motion perception. These measurements set the physical limit at 0.24 cpd (2.1°. Conclusion The maximal spatial information as limited by photoreceptor spacing can not be fully utilized in a motion dependent visual behavior, arguing that the larval zebrafish visual system has not matured enough to optimally translate visual information into behavior. Nevertheless behavioral acuity is remarkable close to its maximal value, given the immature state of young zebrafish larvae.

  17. The urodelean Mauthner cell. Morphology of the afferent synapses to the M-cell of larval Salamandra salamandra

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    Cioni, C.; De Palma, F.; De Vito, L.; Stefanelli, A. [Rome, Univ. (Italy). Dipt. di Biologia Animale e dell`Uomo

    1997-12-31

    In the present work the fine morphology and the distribution of the afferent synapses to the Mauthner cell of larval Salamandra salamandra are described. The aim of the study is to characterize the synaptic bed in the larvae of this terrestrial salamander in order to compare it with that of larval axolotl and larval anurans. Four main types of afferent endings have been identified: myelinated club endings, round-vesicle end bulbs, flattened-vesicle end bulbs and spiral fibers endings. The M-cell afferent synaptology of larval stages of terrestrial amphibians is quite similar to that previously observed in larval stages of aquatic species. This fact can be related to the fundamental similarities between the larval lifestyles.

  18. Larval and nurse worker control of developmental plasticity and the evolution of honey bee queen-worker dimorphism.

    Science.gov (United States)

    Linksvayer, T A; Kaftanoglu, O; Akyol, E; Blatch, S; Amdam, G V; Page, R E

    2011-09-01

    Social evolution in honey bees has produced strong queen-worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental programme includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body size and ovary size for two pairs of honey bee lineages that show similar differences in worker body-ovary size allometry but have diverged over different evolutionary timescales. Our results indicate that the lineages have diverged for both nurse and larval developmental components, that rapid changes in worker body-ovary size allometry may disrupt queen development and that queen-worker dimorphism arises mainly from discrete nurse-provided nutritional environments, not from a developmental switch that converts variable nutritional environments into discrete phenotypes. Both larval and nurse components have likely contributed to the evolution of queen-worker dimorphism.

  19. Larval retention and connectivity among populations of corals and reef fishes: history, advances and challenges

    Science.gov (United States)

    Jones, G. P.; Almany, G. R.; Russ, G. R.; Sale, P. F.; Steneck, R. S.; van Oppen, M. J. H.; Willis, B. L.

    2009-06-01

    The extent of larval dispersal on coral reefs has important implications for the persistence of coral reef metapopulations, their resilience and recovery from an increasing array of threats, and the success of protective measures. This article highlights a recent dramatic increase in research effort and a growing diversity of approaches to the study of larval retention within (self-recruitment) and dispersal among (connectivity) isolated coral reef populations. Historically, researchers were motivated by alternative hypotheses concerning the processes limiting populations and structuring coral reef assemblages, whereas the recent impetus has come largely from the need to incorporate dispersal information into the design of no-take marine protected area (MPA) networks. Although the majority of studies continue to rely on population genetic approaches to make inferences about dispersal, a wide range of techniques are now being employed, from small-scale larval tagging and paternity analyses, to large-scale biophysical circulation models. Multiple approaches are increasingly being applied to cross-validate and provide more realistic estimates of larval dispersal. The vast majority of empirical studies have focused on corals and fishes, where evidence for both extremely local scale patterns of self-recruitment and ecologically significant connectivity among reefs at scales of tens of kilometers (and in some cases hundreds of kilometers) is accumulating. Levels of larval retention and the spatial extent of connectivity in both corals and fishes appear to be largely independent of larval duration or reef size, but may be strongly influenced by geographic setting. It is argued that high levels of both self-recruitment and larval import can contribute to the resilience of reef populations and MPA networks, but these benefits will erode in degrading reef environments.

  20. Larval habitat dynamics and diversity of Culex mosquitoes in rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Shililu, Josephat I; Gu, Weidong; Jacob, Benjamin G; Githure, John I; Novak, Robert J

    2007-01-01

    Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter radius around the study village, including randomly selected paddies and canals, were sampled every two weeks to examine the relationship between vegetation cover, water depth, turbidity, and Culex larval counts. Ten culicine species belonging to four genera were identified, with 73.1% of the total collection comprising of Culex duttoni and Cx. quinquefasciatus. Other species collected included Cx. annulioris, Cx. poicilipes, Cx. cinereus, Cx. tigripes, Cx. trifilatus, Aedes spp., Coquilettidia fuscopennata, and Ficalbia splendens. Murinduko was more diverse than Kiamachiri in terms of species richness (10 versus 7 species) and larval habitat diversity (11 versus 8 habitat types). Paddies, canals, and rain pools were the most diverse habitats in terms of species richness, and ditches, rock pools, and tree holes were the least diverse. Principal component and correlation analyses showed a strong association between three Culex species and the measured habitat characteristics. Culex poicilipes was strongly associated with floating vegetation, Cx. annulioris with clean water containing emergent vegetation, and Cx. quinquefasciatus was associated with turbid water. Seasonal changes in larval counts in water reservoirs and pool and ditch habitats were closely associated with rainfall

  1. Muscle organizers in Drosophila: the role of persistent larval fibers in adult flight muscle development

    Science.gov (United States)

    Farrell, E. R.; Fernandes, J.; Keshishian, H.

    1996-01-01

    In many organisms muscle formation depends on specialized cells that prefigure the pattern of the musculature and serve as templates for myoblast organization and fusion. These include muscle pioneers in insects and muscle organizing cells in leech. In Drosophila, muscle founder cells have been proposed to play a similar role in organizing larval muscle development during embryogenesis. During metamorphosis in Drosophila, following histolysis of most of the larval musculature, there is a second round of myogenesis that gives rise to the adult muscles. It is not known whether muscle founder cells organize the development of these muscles. However, in the thorax specific larval muscle fibers do not histolyze at the onset of metamorphosis, but instead serve as templates for the formation of a subset of adult muscles, the dorsal longitudinal flight muscles (DLMs). Because these persistent larval muscle fibers appear to be functioning in many respects like muscle founder cells, we investigated whether they were necessary for DLM development by using a microbeam laser to ablate them singly and in combination. We found that, in the absence of the larval muscle fibers, DLMs nonetheless develop. Our results show that the persistent larval muscle fibers are not required to initiate myoblast fusion, to determine DLM identity, to locate the DLMs in the thorax, or to specify the total DLM fiber volume. However, they are required to regulate the number of DLM fibers generated. Thus, while the persistent larval muscle fibers are not obligatory for DLM fiber formation and differentiation, they are necessary to ensure the development of the correct number of fibers.

  2. Condition of larval red snapper (Lutjanus campechanus) relative to environmental variability and the Deepwater Horizon oil spill

    Science.gov (United States)

    Hernandez, F. J., Jr.; Filbrun, J. E.; Fang, J.; Ransom, J. T.

    2016-09-01

    The Deepwater Horizon oil spill (DWHOS) spatially and temporally overlapped with the spawning of many fish species, including Red Snapper, one of the most economically important reef fish in the Gulf of Mexico. To investigate potential impacts of the DWHOS on larval Red Snapper, data from a long-term ichthyoplankton survey off the coast of Alabama were used to examine: (1) larval abundances among pre-impact (2007-2009), impact (2010), and post-impact (2011, 2013) periods; (2) proxies for larval condition (size-adjusted morphometric relationships and dry weight) among the same periods; and (3) the effects of background environmental variation on larval condition. We found that larval Red Snapper were in poorer body condition during 2010, 2011, and 2013 as compared to the 2007-2009 period, a trend that was strongly (and negatively) related to variation in Mobile Bay freshwater discharge. However, larvae collected during and after 2010 were in relatively poor condition even after accounting for variation in freshwater discharge and other environmental variables. By contrast, no differences in larval abundance were detected during these survey years. Taken together, larval supply did not change relative to the timing of the DWHOS, but larval condition was negatively impacted. Even small changes in condition can affect larval survival, so these trends may have consequences for recruitment of larvae to juvenile and adult life stages.

  3. Role of circulation scales and water mass distributions on larval fish habitats in the Eastern Tropical Pacific off Mexico

    Science.gov (United States)

    León-Chávez, Cristina A.; Beier, Emilio; Sánchez-Velasco, Laura; Barton, Eric Desmond; Godínez, Victor M.

    2015-06-01

    On the basis of five oceanographic cruises carried out in the Eastern Tropical Pacific off Mexico, relationships between the larval fish habitats (areas inhabited by larval fish assemblages) and the environmental circulation scales (mesoscale, seasonal, and interannual) were examined. Analysis of in situ data over a grid of hydrographic stations and oblique zooplankton hauls with bongo net (505 µm) was combined with orthogonal robust functions decomposition applied to altimetry anomalies obtained from satellite. During both cool (March and June) and warm (August and November) periods, Bray-Curtis dissimilarity Index defined three recurrent larval fish habitats which varied in species composition and extent as a function of the environmental scales. The variability of the Tropical larval fish habitat (characterized by high species richness, and dominated by Vinciguerria lucetia, Diogenichthys laternatus, and Diaphus pacificus) was associated with the seasonal changes. The Transitional-California Current larval fish habitat (dominated by V. lucetia and D. laternatus, with lower mean abundance and lower species richness than in the Tropical habitat) and Coastal-and-Upwelling larval fish habitat (dominated by Bregmaceros bathymaster) was associated mainly with mesoscale activity induced by eddies and with coastal upwelling. During February 2010, the Tropical larval fish habitat predominated offshore and the Transitional-California Current larval fish habitat was not present, which we attribute to the effect of El Niño conditions. Thus, the mesoscale, seasonal, and interannual environmental scales affect the composition and extension of larval fish habitats.

  4. Obligate larval inhibition of Ostertagia gruehneri in Rangifer tarandus? Causes and consequences in an Arctic system.

    Science.gov (United States)

    Hoar, Bryanne M; Eberhardt, Alexander G; Kutz, Susan J

    2012-09-01

    Larval inhibition is a common strategy of Trichostrongylidae nematodes that may increase survival of larvae during unfavourable periods and concentrate egg production when conditions are favourable for development and transmission. We investigated the propensity for larval inhibition in a population of Ostertagia gruehneri, the most common gastrointestinal Trichostrongylidae nematode of Rangifer tarandus. Initial experimental infections of 4 reindeer with O. gruehneri sourced from the Bathurst caribou herd in Arctic Canada suggested that the propensity for larval inhibition was 100%. In the summer of 2009 we infected 12 additional reindeer with the F1 and F2 generations of O. gruehneri sourced from the previously infected reindeer to further investigate the propensity of larval inhibition. The reindeer were divided into 2 groups and half were infected before the summer solstice (17 June) and half were infected after the solstice (16 July). Reindeer did not shed eggs until March 2010, i.e. 8 and 9 months post-infection. These results suggest obligate larval inhibition for at least 1 population of O. gruehneri, a phenomenon that has not been conclusively shown for any other trichostrongylid species. Obligate inhibition is likely to be an adaptation to both the Arctic environment and to a migratory host and may influence the ability of O. gruehneri to adapt to climate change.

  5. Circulation constrains the evolution of larval development modes and life histories in the coastal ocean.

    Science.gov (United States)

    Pringle, James M; Byers, James E; Pappalardo, Paula; Wares, John P; Marshall, Dustin

    2014-04-01

    The evolutionary pressures that drive long larval planktonic durations in some coastal marine organisms, while allowing direct development in others, have been vigorously debated. We introduce into the argument the asymmetric dispersal of larvae by coastal currents and find that the strength of the currents helps determine which dispersal strategies are evolutionarily stable. In a spatially and temporally uniform coastal ocean of finite extent, direct development is always evolutionarily stable. For passively drifting larvae, long planktonic durations are stable when the ratio of mean to fluctuating currents is small and the rate at which larvae increase in size in the plankton is greater than the mortality rate (both in units of per time). However, larval behavior that reduces downstream larval dispersal for a given time in plankton will be selected for, consistent with widespread observations of behaviors that reduce dispersal of marine larvae. Larvae with long planktonic durations are shown to be favored not for the additional dispersal they allow, but for the additional fecundity that larval feeding in the plankton enables. We analyzed the spatial distribution of larval life histories in a large database of coastal marine benthic invertebrates and documented a link between ocean circulation and the frequency of planktotrophy in the coastal ocean. The spatial variation in the frequency of species with planktotrophic larvae is largely consistent with our theory; increases in mean currents lead to a decrease in the fraction of species with planktotrophic larvae over a broad range of temperatures.

  6. Identification of genes differentially expressed during larval molting and metamorphosis of Helicoverpa armigera

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    Jiang Xiao-Juan

    2007-06-01

    Full Text Available Abstract Background Larval molting and metamorphosis are important physiological processes in the life cycle of the holometabolous insect. We used suppression subtractive hybridization (SSH to identify genes differentially expressed during larval molting and metamorphosis. Results We performed SSH between tissues from a variety of developmental stages, including molting 5th and feeding 6th instar larvae, metamorphically committed and feeding 5th instar larvae, and feeding 5th instar and metamorphically committed larvae. One hundred expressed sequence tags (ESTs were identified and included 73 putative genes with similarity to known genes, and 27 unknown ESTs. SSH results were further characterized by dot blot, Northern blot, and RT-PCR. The expression levels of eleven genes were found to change during larval molting or metamorphosis, suggesting a functional role during these processes. Conclusion These results provide a new set of genes expressed specifically during larval molt or metamorphosis that are candidates for further studies into the regulatory mechanisms of those stage-specific genes during larval molt and metamorphosis

  7. The Drosophila gene RanBPM functions in the mushroom body to regulate larval behavior.

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    Nadia Scantlebury

    Full Text Available BACKGROUND: In vertebrates, Ran-Binding Protein in the Microtubule Organizing Center (RanBPM appears to function as a scaffolding protein in a variety of signal transduction pathways. In Drosophila, RanBPM is implicated in the regulation of germ line stem cell (GSC niche organization in the ovary. Here, we addressed the role of RanBPM in nervous system function in the context of Drosophila larval behavior. METHODOLOGY/PRINCIPAL FINDINGS: We report that in Drosophila, RanBPM is required for larval feeding, light-induced changes in locomotion, and viability. RanBPM is highly expressed in the Kenyon cells of the larval mushroom body (MB, a structure well studied for its role in associative learning in Drosophila and other insects. RanBPM mutants do not display major disruption in nervous system morphology besides reduced proliferation. Expression of the RanBPM gene in the Kenyon cells is sufficient to rescue all behavioral phenotypes. Through genetic epistasis experiments, we demonstrate that RanBPM participates with the Drosophila orthologue of the Fragile X Mental Retardation Protein (FMRP in the development of neuromuscular junction (NMJ. CONCLUSIONS/SIGNIFICANCE: We demonstrate that the RanBPM gene functions in the MB neurons for larval behavior. Our results suggest a role for this gene in an FMRP-dependent process. Taken together our findings point to a novel role for the MB in larval behavior.

  8. Evidence and population consequences of shared larval dispersal histories in a marine fish.

    Science.gov (United States)

    Shima, Jeffrey S; Swearer, Stephen E

    2016-01-01

    Larval dispersal is disproportionately important for marine population ecolgy and evolution, yet our inability to track individuals severely constrains our understanding of this key process. We analyze otoliths of a small reef fish, the common triplefin (Forsterygion lapillum), to reconstruct individual dispersal histories and address the following questions: (1) How many discrete sets of dispersal histories (dispersal cohorts) contribute to replenishment of focal populations; (2) When do dispersal cohorts converge (a metric of shared dispersal histories among cohorts); and (3) Do these patterns predict spatiotemporal variation in larval supply? We used light traps to quantify larval supply, and otolith microstructure and microchemistry (using laser ablation inductively coupled plasma mass spectrometry; LA-ICP-MS) to reconstruct daily environmental histories of individuals in their 30-d lead-up to settlement. Our results indicate that a variable number of dispersal cohorts replenish focal populations (range of 2-8, mean of 4.3, standard deviation of 2.8). Convergence times varied (from 0 to > 30 d prior to settlement), and larval supply was negatively correlated with cohort evenness but not with the number of cohorts, or when they converged, indicating disproportionately large contributions from some cohorts (i.e., sweepstakes events). Collectively, our results suggest that larval reef fishes may variably disperse in shoals, to drive local replenishment and connectivity within a metapopulation.

  9. Soundscape manipulation enhances larval recruitment of a reef-building mollusk

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    Ashlee Lillis

    2015-06-01

    Full Text Available Marine seafloor ecosystems, and efforts to restore them, depend critically on the influx and settlement of larvae following their pelagic dispersal period. Larval dispersal and settlement patterns are driven by a combination of physical oceanography and behavioral responses of larvae to a suite of sensory cues both in the water column and at settlement sites. There is growing evidence that the biological and physical sounds associated with adult habitats (i.e., the “soundscape” influence larval settlement and habitat selection; however, the significance of acoustic cues is rarely tested. Here we show in a field experiment that the free-swimming larvae of an estuarine invertebrate, the eastern oyster, respond to the addition of replayed habitat-related sounds. Oyster larval recruitment was significantly higher on larval collectors exposed to oyster reef sounds compared to no-sound controls. These results provide the first field evidence that soundscape cues may attract the larval settlers of a reef-building estuarine invertebrate.

  10. Blue light-induced immunosuppression in Bactrocera dorsalis adults, as a carryover effect of larval exposure.

    Science.gov (United States)

    Tariq, K; Noor, M; Hori, M; Ali, A; Hussain, A; Peng, W; Chang, C-J; Zhang, H

    2017-05-09

    Detrimental effects of ultraviolet (UV) light on living organisms are well understood, little is known about the effects of blue light irradiation. Although a recent study revealed that blue light caused more harmful effects on insects than UV light and blue light irradiation killed insect pests of various orders including Diptera, the effects of blue light on physiology of insects are still largely unknown. Here we studied the effects of blue light irradiation on cuticular melanin in larval and the immune response in adult stage of Bactrocera dorsalis. We also evaluated the effects of blue light exposure in larval stage on various age and mass at metamorphosis and the mediatory role of cuticular melanin in carryover effects of larval stressors across metamorphosis. We found that larvae exposed to blue light decreased melanin contents in their exoskeleton with smaller mass and delayed metamorphosis than insects reared without blue light exposure. Across metamorphosis, lower melanotic encapsulation response and higher susceptibility to Beauveria bassiana was detected in adults that had been exposed to blue light at their larval stage, thereby constituting the first evidence that blue light impaired adult immune function in B. dorsalis as a carryover effect of larval exposure.

  11. Juvenile hormone-mediated termination of larval diapause in the bamboo borer, Omphisa fuscidentalis.

    Science.gov (United States)

    Singtripop, T; Wanichacheewa, S; Sakurai, S

    2000-01-01

    Larvae of the bamboo borer, Omphisa fuscidentalis are in diapause for more than nine months (Singtripop, T., Wanichaneewa, S., Tsuzuki, S., Sakurai, S. 1999. Larval growth and diapause in a tropical moth, Omphisa fuscidentalis Hampson. Zool. Sci. 16, 725-733). To examine the endocrine mechanisms underlying this larval diapause, we assayed the responsiveness of the diapausing larvae to 20-hydroxyecdysone (20E) and a juvenile hormone analogue (JHA: S-methoprene). 20E injection caused the larvae to halt movement, followed by deposition of a pupal cuticle. Topical application of JHA induced pupation in a dose-dependent manner. JHA also induced pupation of the larvae whose brains were removed before JHA application. In those larvae, the prothoracic glands became active and competent to respond to brain extracts within seven days after JHA treatment, and the hemolymph ecdysteroid concentration began to increase 12 days after JHA application. These results indicate that JHA stimulates the prothoracic glands of diapausing Omphisa larvae, terminating larval diapause, in contrast with previous findings that JH inhibits the brain-prothoracic gland axis and thus maintains the larval diapause. Current results therefore suggest a novel regulatory mechanism for larval diapause in this species.

  12. Embryogenesis and larval biology of the cold-water coral Lophelia pertusa.

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    Ann I Larsson

    Full Text Available Cold-water coral reefs form spectacular and highly diverse ecosystems in the deep sea but little is known about reproduction, and virtually nothing about the larval biology in these corals. This study is based on data from two locations of the North East Atlantic and documents the first observations of embryogenesis and larval development in Lophelia pertusa, the most common framework-building cold-water scleractinian. Embryos developed in a more or less organized radial cleavage pattern from ∼ 160 µm large neutral or negatively buoyant eggs, to 120-270 µm long ciliated planulae. Embryogenesis was slow with cleavage occurring at intervals of 6-8 hours up to the 64-cell stage. Genetically characterized larvae were sexually derived, with maternal and paternal alleles present. Larvae were active swimmers (0.5 mm s(-1 initially residing in the upper part of the water column, with bottom probing behavior starting 3-5 weeks after fertilization. Nematocysts had developed by day 30, coinciding with peak bottom-probing behavior, and possibly an indication that larvae are fully competent to settle at this time. Planulae survived for eight weeks under laboratory conditions, and preliminary results indicate that these planulae are planktotrophic. The late onset of competency and larval longevity suggests a high dispersal potential. Understanding larval biology and behavior is of paramount importance for biophysical modeling of larval dispersal, which forms the basis for predictions of connectivity among populations.

  13. Nutritional value-dependent and nutritional value-independent effects on Drosophila melanogaster larval behavior.

    Science.gov (United States)

    Rohwedder, Astrid; Pfitzenmaier, Johanna E; Ramsperger, Noel; Apostolopoulou, Anthi A; Widmann, Annekathrin; Thum, Andreas S

    2012-10-01

    Gustatory stimuli allow an organism not only to orient in its environment toward energy-rich food sources to maintain nutrition but also to avoid unpleasant or even poisonous substrates. For both mammals and insects, sugars-perceived as "sweet"-potentially predict nutritional benefit. Interestingly, even Drosophila adult flies are attracted to most high-potency sweeteners preferred by humans. However, the gustatory information of a sugar may be misleading as some sugars, although perceived as "sweet," cannot be metabolized. Accordingly, in adult Drosophila, a postingestive system that additionally evaluates the nutritional benefit of an ingested sugar has been shown to exist. By using a set of seven different sugars, which either offer (fructose, sucrose, glucose, maltodextrin, and sorbitol) or lack (xylose and arabinose) nutritional benefit, we show that Drosophila, at the larval stage, can perceive and evaluate sugars based on both nutrition-dependent and -independent qualities. In detail, we find that larval survival and feeding mainly depend on the nutritional value of a particular sugar. In contrast, larval choice behavior and learning are regulated in a more complex way by nutrition value-dependent and nutrition value-independent information. The simplicity of the larval neuronal circuits and their accessibility to genetic manipulation may ultimately allow one to identify the neuronal and molecular basis of the larval sugar perception systems described here behaviorally.

  14. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan

    2012-08-01

    The polychaete . Hydroides elegans (Serpulidae, Lophotrochozoa) is a problematic marine fouling organism in most tropical and subtropical coastal environment. Competent larvae of . H. elegans undergo the transition from the swimming larval stage to the sessile juvenile stage with substantial morphological, physiological, and behavior changes. This transition is often referred to as larval settlement and metamorphosis. In this study, we examined the possible involvement of calmodulin (CaM) - a multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid residues. It was highly expressed in 12. h post-metamorphic juveniles, and remained high in adults. . In situ hybridization conducted in competent larvae and juveniles revealed that . He-CaM gene was continuously expressed in the putative growth zones, branchial rudiments, and collar region, suggesting that . He-CaM might be involved in tissue differentiation and development. Our subsequent bioassay revealed that the CaM inhibitor W7 could effectively inhibit larval settlement and metamorphosis, and cause some morphological defects of unsettled larvae. In conclusion, our results revealed that CaM has important functions in the larval settlement and metamorphosis of . H. elegans. © 2012 Elsevier Inc..

  15. Patterning the dorsal longitudinal flight muscles (DLM) of Drosophila: insights from the ablation of larval scaffolds

    Science.gov (United States)

    Fernandes, J. J.; Keshishian, H.

    1996-01-01

    The six Dorsal Longitudinal flight Muscles (DLMs) of Drosophila develop from three larval muscles that persist into metamorphosis and serve as scaffolds for the formation of the adult fibers. We have examined the effect of muscle scaffold ablation on the development of DLMs during metamorphosis. Using markers that are specific to muscle and myoblasts we show that in response to the ablation, myoblasts which would normally fuse with the larval muscle, fuse with each other instead, to generate the adult fibers in the appropriate regions of the thorax. The development of these de novo DLMs is delayed and is reflected in the delayed expression of erect wing, a transcription factor thought to control differentiation events associated with myoblast fusion. The newly arising muscles express the appropriate adult-specific Actin isoform (88F), indicating that they have the correct muscle identity. However, there are frequent errors in the number of muscle fibers generated. Ablation of the larval scaffolds for the DLMs has revealed an underlying potential of the DLM myoblasts to initiate de novo myogenesis in a manner that resembles the mode of formation of the Dorso-Ventral Muscles, DVMs, which are the other group of indirect flight muscles. Therefore, it appears that the use of larval scaffolds is a superimposition on a commonly used mechanism of myogenesis in Drosophila. Our results show that the role of the persistent larval muscles in muscle patterning involves the partitioning of DLM myoblasts, and in doing so, they regulate formation of the correct number of DLM fibers.

  16. Larval starvation reduces responsiveness to feeding stimuli and does not affect feeding preferences in a butterfly.

    Science.gov (United States)

    Kehl, Tobias; Fischer, Klaus

    2012-07-01

    It is commonly assumed that holometabolic insects such as Lepidoptera rely primarily on larval storage reserves for reproduction. Recent studies though have documented a prominent role of adult-derived carbohydrates for butterfly reproduction. Moreover, a few studies have shown that adult butterflies may also benefit from adult-derived amino acids, at least when larval storage reserves are reduced. Given that in holometabolous insects larval deficiencies are carried over into the adult stage, reduced storage reserves have the potential to modulate adult feeding preferences and responses in order to allow for a successful compensation. We tested this hypothesis here in the fruit-feeding butterfly Bicyclus anynana using larval food stress to manipulate storage reserves. Alcohols (methanol, ethanol, butanol, propanol), sugars (maltose, glucose, fructose, sucrose), and acetic acid acted as feeding stimuli, while butterflies did not respond to other substances such as amino acids, yeast, salts, or vitamins. Contrary to expectations, stressed butterflies showed a weaker response than controls to several feeding stimuli. In preference tests, butterflies preferred sugar solutions containing proline, arginine, glutamic acid, acetic acid, or ethanol over plain sugar solutions, but discriminated against salts. However, there were no general differences among starved and control butterflies. We conclude that larval food-stress does not elicit compensatory feeding behavior such as a stronger preference for amino acids or other essential nutrients in B. anynana. Instead, the stress imposed by a period of starvation yielded negative effects. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. [Carbohydrate restriction in the larval diet causes oxidative stress in adult insects of Drosophila melanogaster].

    Science.gov (United States)

    Rovenko, B M; Lushchak, V I; Lushchak, O V

    2013-01-01

    The influence of 20 and 1% glucose and fructose, which were components of larval diet, on the level of oxidized proteins and lipids, low molecular mass antioxidant content as well as activities of antioxidant and associated enzymes in adult fruit fly Drosophila melanogaster were investigated. The restriction of carbohydrates in larval diet leads to oxidative stress in adult insects. It is supported by 40-50% increased content of protein carbonyl groups and by 60-70% decreased level of protein thiol groups as well as by a 4-fold increase of lipid peroxide content in 2-day-old flies of both sexes, developed on the diet with 1% carbohydrates. Oxidative stress, induced by carbohydrate restriction of the larval diet, caused the activation of antioxidant defence, differently exhibited in male and female fruit flies. Caloric restriction increased activity of superoxide dismutase and thioredoxin reductase associating only in males with 2-fold higher activity of NADPH-producing enzymes--glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase. Carbohydrate restriction in the larval diet caused the increase of uric acid content, but the decrease in catalase activity in males. In females the values of these parameters were changed in opposite direction compared with males. The obtained results let us conclude the different involvement of low molecular mass antioxidants, glutathione and uric acid, and antioxidant enzyme catalase in the protection of male and female fruit fly macromolecules against oxidative damages, caused by calorie restriction of larval diet.

  18. Larval Fish Assemblages, Environment and Circulation in a Semienclosed Sea (Gulf Of California).

    Science.gov (United States)

    Peguero, M.; Sánchez-Velasco, L.; Lavín, M.; Marinone, G.

    2007-05-01

    Fish larvae and hydrographic data collected in the Gulf of California in December 2002 are used to describe the larval fish assemblages and to explore their relationships with environmental variables. The Bray-Curtis dissimilarity index defined three larval fish assemblages, whose goeographical distribution coincided with three areas defined by Principal Component Analysis of the environmental variables. The affinity of most of the species with the environmental characteristics of their areas of distribution could be interpreted as an indication that spawning occurred inside those areas. However, it is not known when the spawning took place, and the fast currents in the Gulf could rapidly disperse eggs and larvae. Since transport and retention is best studied from a Lagrangian point of view, the currents from a 3D numerical model were used to track large numbers of particles released in the different larval fish assemblage areas. Particle-tracking and connectivity matrices can help in assessing larval fish retention in seas that, like the Gulf of California, have well defined circulation patterns. On time scales around 30 days, retention occurred for the North assemblage in the Upper Gulf, for the Channel- Central assemblage in the anticyclone over the Norhern Gulf and in Ballenas Channel, and for the South assemblage in the eddy over San Pedro Mártir basin and in the shallow zone off the peninsula. Therefore, the Lagrangian analysis revealed that the observed larval fish assemblages have a permanency long enough to allow the larve to remain in a favorable environment until they develop motility.

  19. Taenia taeniaeformis larval product induces gastric mucosal hyperplasia in SCID mice.

    Science.gov (United States)

    Lagapa, Jose Trinipil G; Oku, Yuzaburo; Nonaka, Nariaki; Kamiya, Masao

    2002-02-01

    The effects of intraperitoneal implantation of Taenia taeniaeformis larvae and inoculation of in vitro larval products on gastric mucosa of SCID mice were investigated in this study. Mice surgically implanted with T. taeniaeformis larvae developed slight and moderate gastric hyperplasia. When in vitro cultured T. taeniaeformis larval excretory-secretory (TtLES) products containing 1 mg of protein were injected daily into mice, they caused gastropathy after 5-7 days. Mice injected daily with 0.5 mg of TtLES products also showed slight gastric hyperplasia after day 14 and 28. The gastropathy was characterized by reduction of both parietal and zymogenic cell number and increased number of alcian blue-periodic acid Schiff (AB-PAS)-positive cells and by two-fold extension of proliferative zone of gastric units. Larval implantation demonstrated a more potent effect in inducing gastropathy than did in vitro larval culture products. Significant decrease in number of parietal cells with concomitant increase of proliferative zone and AB-PAS-positive cell number indicated their important roles in inducing the hyperplastic lesion. Similarities with other gastropathies indicated that there is a common fundamental regulatory mechanism involved, and that the host response may not be specific to parasites. Present study validated the induction of gastric mucosal hyperplasia by larval ES products of T. taeniaeformis. This proved the hypothesis of previous studies suggesting the role of larvae-derived products in inducing gastric mucosal hyperplasia in T. taeniaeformis-infected rats.

  20. Predator-induced larval cloning in the sand dollar Dendraster excentricus: might mothers matter?

    Science.gov (United States)

    Vaughn, Dawn

    2009-10-01

    Predator-induced cloning in echinoid larvae, with reduced size a consequence of cloning, is a dramatic modification of development and a novel response to risks associated with prolonged planktonic development. Recent laboratory studies demonstrate that exposure to stimuli from predators (i.e., fish mucus) induces cloning in the pluteus larvae (plutei) of Dendraster excentricus. However, the timing and incidence of cloning and size reduction of unrelated conspecific plutei differed across experiments. A variable cloning response suggests the effects of such factors as cue quality, egg provisioning, maternal experience, and genetic background, indicating that the potential advantages of cloning as an adaptive response to predators are not available to all larvae. This study tested the hypothesis that cloning in D. excentricus plutei is maternally influenced. Plutei from three half-sibling larval families (different mothers, same father) were exposed to fish mucus for 9 days during early development. Cloning was inferred in a percentage of plutei from each family; however, the rate and success of cloning differed significantly among the larval half-siblings. Unexpectedly, all mucus-treated plutei were smaller and developmentally delayed when compared to all plutei reared in the absence of a mucus stimulus. Thus, while the results from this study support the hypothesis of an influence of mothers on cloning of larval offspring, reduced larval size was a uniform response to fish mucus and did not indicate an effect of mothers. Hypotheses of the developmental effects of fish mucus on larval size with or without successful cloning are discussed.

  1. Acondicionamiento de reproductores, desove y cultivo larval de Graus nigra (Philippi, 1887 (Kyphosidae: Girellinae Broodstock conditioning, spawning and larval culture of Graus nigra (Philippi, 1887 (Kyphosidae: Girellinae

    Directory of Open Access Journals (Sweden)

    Avelino Muñoz

    2012-09-01

    Full Text Available Se describen resultados sobre acondicionamiento reproductivo, desove y cultivo larval de Graus nigra ("vieja negra", "mulata". Peces adultos silvestres se recolectaron y se utilizaron como reproductores, los que al final del período de acondicionamiento alcanzaron el estado de maduración gonadal y desovaron en forma natural y espontánea. Los huevos fueron recolectados y después de 36 h de incubación eclosionaron, con una tasa de eclosión promedio de 60%. Las larvas recién eclosionadas midieron 2,9 ± 0,23 mm y alcanzaron el día 50 post-eclosión (PE una longitud total de 12,6 ± 0,37 mm. La sobrevivencia larval posterior a la eclosión fue entre 50,9 y 79,1% y al día 30 PE fue de 12,1%. El cultivo larval se desarrolló en estanques con suministro de agua de mar filtrada y esterilizada. Después de la reabsorción del saco vitelino se produjo el desarrollo del tracto digestivo y las larvas se alimentaron con dieta viva enriquecida con emulsión de ácidos grasos altamente insaturados. A los 35 días de cultivo se ofreció alimento artificial a las larvas cuyo tamano fue aumentando progresivamente a medida que progresó su desarrollo ontogénico. Se describe la evolución anatómica de las larvas y las relaciones morfométricas que representan su desarrollo; se caracteriza el patrón de crecimiento de las larvas hasta los 50 días post-eclosión y se discuten aspectos relacionados con la sobrevivencia larval y la introducción de mejoras para optimizar la producción de larvas y juveniles.In this study results related to reproductive conditioning, spawning and larval culture of Graus nigra ("vieja negra", "mulata" are given. Wild adult fishes were collected and used as brooders which at the end of the conditioning period reached gonadal maturation state and spawned naturally and spontaneously. Eggs were collected and after 36 hours of incubation they hatched at average rate of 60%. The hatched larvae measured 2.9 ± 0.23 mm and at day 50

  2. Genetic and evolutionary analysis of the Drosophila larval neuromuscular junction

    Science.gov (United States)

    Campbell, Megan

    Although evolution of brains and behaviors is of fundamental biological importance, we lack comprehensive understanding of the general principles governing these processes or the specific mechanisms and molecules through which the evolutionary changes are effected. Because synapses are the basic structural and functional units of nervous systems, one way to address these problems is to dissect the genetic and molecular pathways responsible for morphological evolution of a defined synapse. I have undertaken such an analysis by examining morphology of the larval neuromuscular junction (NMJ) in wild caught D. melanogaster as well as in over 20 other species of Drosophila. Whereas variation in NMJ morphology within a species is limited, I discovered a surprisingly extensive variation among different species. Compared with evolution of other morphological traits, NMJ morphology appears to be evolving very rapidly. Moreover, my data indicate that natural selection rather than genetic drift is primarily responsible for evolution of NMJ morphology. To dissect underlying molecular mechanisms that may govern NMJ growth and evolutionary divergence, I focused on a naturally occurring variant in D. melanogaster that causes NMJ overgrowth. I discovered that the variant mapped to Mob2, a gene encoding a kinase adapter protein originally described in yeast as a member of the Mitotic Exit Network (MEN). I have subsequently examined mutations in the Drosophila orthologs of all the core components of the yeast MEN and found that all of them function as part of a common pathway that acts presynaptically to negatively regulate NMJ growth. As in the regulation of yeast cytokinesis, these components of the MEN appear to act ultimately by regulating actin dynamics during the process of bouton growth and division. These studies have thus led to the discovery of an entirely new role for the MEN---regulation of synaptic growth---that is separate from its function in cell division. This work

  3. A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe.

    Science.gov (United States)

    Perry, J N; Devos, Y; Arpaia, S; Bartsch, D; Gathmann, A; Hails, R S; Kiss, J; Lheureux, K; Manachini, B; Mestdagh, S; Neemann, G; Ortego, F; Schiemann, J; Sweet, J B

    2010-05-01

    Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality-dose relationship was integrated with a dose-distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

  4. Stability of Bacillus thuringiensis and NPV Microencapsulated Formulation under Sunlight

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Naghavi

    2016-06-01

    Full Text Available Microencapsulation technology is used for the formulation of bio pesticides and is effective against the ultra-violet radiation of sunlight. The present research studied the stability of Bt and NPV formulations microencapsulated with gelatin and sodium alginate, individually or in combination. The formulations were evaluated in outdoor space and under sunlight on potted growing cabbage. The stability of each active ingredient tested in each formulation was studied at 0, 3, 7 and 10 days after spraying on cabbage infested with diamondback moth Plutella xylostella second instars larvae. Results showed that non-formulated and microencapsulated formulations not exposed to sunlight (time zero had similar mortality. However, after being exposed to sunlight for three days, the non-formulated Bt and NPV resulted in a significantly lower mortality (less than 40%; compared with the microencapsulated bio pesticides (more than 70% mortality. Fifty percent (50% mortality was reached in microencapsulated formulations after seven and ten days of exposure to sunlight, whereas there was no mortality in larvae exposed to unformulated treated plants after ten days. ANOVA analysis showed the highest larval mortality was achieved by the Bt+NPV gelatin microencapsulated formulation followed by gelatin coated Bt, sodium alginate coated NPV, sodium alginate coated Bt+NPV, gelatin coated NPV and sodium alginate coated Bt. The formulations showed no significant LT50 differences between microencapsulated versus unformulated Bt and NPV.

  5. Atmospheric transformation of plant volatiles disrupts host plant finding

    Science.gov (United States)

    Li, Tao; Blande, James D.; Holopainen, Jarmo K.

    2016-09-01

    Plant-emitted volatile organic compounds (VOCs) play important roles in plant-insect interactions. Atmospheric pollutants such as ozone (O3) can react with VOCs and affect the dynamics and fidelity of these interactions. However, the effects of atmospheric degradation of plant VOCs on plant-insect interactions remains understudied. We used a system comprising Brassica oleracea subsp. capitata (cabbage) and the specialist herbivore Plutella xylostella to test whether O3-triggered VOC degradation disturbs larval host orientation, and to investigate the underlying mechanisms. Larvae oriented towards both constitutive and larva-induced cabbage VOC blends, the latter being the more attractive. Such behaviour was, however, dramatically reduced in O3-polluted environments. Mechanistically, O3 rapidly degraded VOCs with the magnitude of degradation increasing with O3 levels. Furthermore, we used Teflon filters to collect VOCs and their reaction products, which were used as odour sources in behavioural tests. Larvae avoided filters exposed to O3-transformed VOCs and spent less time searching on them compared to filters exposed to original VOCs, which suggests that some degradation products may have repellent properties. Our study clearly demonstrates that oxidizing pollutants in the atmosphere can interfere with insect host location, and highlights the need to address their broader impacts when evaluating the ecological significance of VOC-mediated interactions.

  6. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

    2009-01-15

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

  7. Low larval densities in northern populations reinforce range expansion by a Mediterranean damselfly

    DEFF Research Database (Denmark)

    Therry, Lieven; Swaegers, Janne; Dinh, Khuong Van

    2016-01-01

    towards the very edge of the expansion front has been neglected. Density effects may, however, have a profound direct impact on traits involved in range expansion and influence range dynamics. 2. In this study, we contrast the effects of high conspecific larval density typical for established populations...... and low larval density typical for newly founded populations at the edge of the expansion front on a set of larval traits that may affect the range dynamics in the poleward moving damselfly Coenagrion scitulum. We therefore ran an outdoor mesocosm experiment with a low- and high-density treatment close......, fat content and activity of phenoloxidase (PO)] was scored at the end of the winter period. 3. The low-density treatment had strong direct positive effects on survival, growth rate and body size of larvae before winter indicating relaxed competition. Lower foraging activity at the lowdensity treatment...

  8. Larval spirurida (Nematoda) from the crab Macrophthalmus hirtipes in New Zealand

    DEFF Research Database (Denmark)

    Moravec, Frantisek; Fredensborg, Brian Lund; Latham, A David M;

    2003-01-01

    Previously undescribed third-stage larvae of two species of Spirurida were found in the haemocoel of the stalk-eyed mud crab Macrophthalmus hirtipes (Heller) (Ocypodidae) in New Zealand. Examinations by light and scanning electron microscopy showed that the larger larvae (about 7 mm long) belonged...... from Papanui Inlet, on Otago Peninsula, South Island, 74 crabs (90.2%) were infected with larval nematodes with an intensity of 1-18 (mean 4.6) nematodes per crab; no distinction between nematode species was made in these estimates, although juvenile Acuariidae greatly outnumbered larval Ascarophis....... Apparently, crabs play a role as intermediate hosts of these nematode species. This is the first record of larval representatives of Cystidicolidae and Acuariidae from invertebrates in the Australasian Region....

  9. Prey size spectra and prey availability of larval and small juvenile cod

    DEFF Research Database (Denmark)

    Munk, Peter

    1997-01-01

    The aim of the present study is to describe the prey preference characteristics of cod larvae and assess preference variability in relation to species and size composition of copepod prey. A further aim is to examine the hypothesis that dietary prey size spectra remain the same during the larval...... stage when viewed on a relative predator/prey size scale. The study is based on stomach analysis of larval/juvenile cod in the size range 10-35 mm from nursery grounds in the North Sea. Stomach contents (species, size) were compared to environmental composition and preference indices were calculated....... Prey size spectra had the expected relationship to larval cod size, and preference for given copepod species could be ascribed to their relative size; Additional species-specific preferences were evident, for example the larger Pseudocalanus and the larger Calanus spp. were highly preferred. Available...

  10. Ovarian development and early larval survival of Stenopus zanzibaricus (Bruce, 1976

    Directory of Open Access Journals (Sweden)

    Daniel Marques

    2014-06-01

    Full Text Available Despite economically valuable, ornamental shrimps are poorly studied and there is a lack of protocols for their captive breeding. Stenopus is one of the most important genera of ornamental shrimps, being Stenopus zanzibaricus one of the species with less information about captive breeding and larviculture. For a better knowledge of its reproductive cycle, we evaluated morphological and color changes during ovarian development of adult females through daily photographs taken during all the cycle. The effect of three diets (Brachionus plicatilis + Tetraselmis chuii; newly artemia nauplii + Tetraselmis chuii; newly artemia nauplii and two different temperatures (25ºC and 27ºC on early larval development were also evaluated. With this study, it was expected to obtain some insight about Stenopus zanzibaricus reproductive cycle and early larval development, in order to develop captive breeding and larval rearing protocols for this economic valuable species.

  11. A description of the larval development of Megabalanus azoricus (Pilsbry, 1916) reared in the laboratory

    Science.gov (United States)

    Dionísio, Maria; Rodrigues, Armindo; Costa, Ana

    2014-03-01

    This study provides the first description of the larval development of the commercially exploited barnacle Megabalanus azoricus. It describes the changes in larval size and shape as well as the general morphology and duration of each larval stage. Embryos were obtained from gravid specimens collected at São Miguel Island and reared through six naupliar stages to the cypris stage in laboratory conditions. The planktotrophic nauplii reached the cypris stage after 14 days of hatching in individual cultures at 20 °C under natural illumination and fed with phytoplankton ( Chaetoceros gracilis, Isochrysis sp., and Tetraselmis sp.). The nauplius of M. azoricus has a normal size compared with nauplii of other congeneric species, ranging between the 261 μm (nauplius I) and 912 μm (nauplius VI). This work provides the first description of larvae of the genus Megabalanus for the Portuguese oceanic islands and provides comparisons with congeneric species in other parts of the world.

  12. Predation by odonate nymphs on larval razorback suckers (Xyrauchen texanus) under laboratory conditions

    Science.gov (United States)

    Horn, Michael J.; Marsh, Paul C.; Mueller, Gordon; Burke, Tom

    1994-01-01

    High larval mortality has plagued efforts to raise razorback suckers (Xyrauchen texanus) in a Lake Mohave, Arizona-Nevada backwater. Observations indicate odonate nymph densities may be high enough to impact larval survival. In laboratory tests conducted in aquaria, damselfly (Coenagrionidae: Enallagma sp.) and dragonfly (Libellulidae: Tramea sp.) nymphs consumed 81% and 76% respectively of 11.8 ± 0.7 mm total length larval razorbacks in 7 days compared to 12% mortality in controls. Larger razorback larvae (14 to 15 mm TL) were less susceptible than smaller fish, showing 53% mortality versus 18% in controls. Extensive growth of sago pondweed (Potamogeton pectinatus) may exacerbate predation effects in the backwater, by allowing odonates access to more of the water column.

  13. Larval starvation to satiation: influence of nutrient regime on the success of Acanthaster planci.

    Directory of Open Access Journals (Sweden)

    Kennedy Wolfe

    Full Text Available High density populations of the crown-of-thorns seastar, Acanthaster planci, are a major contributor to the decline of coral reefs, however the causes behind periodic outbreaks of this species are not understood. The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth. The larval resilience hypothesis suggests that A. planci larvae naturally thrive in tropical oligotrophic waters. Both hypotheses remain to be tested empirically. We raised A. planci larvae in a range of food regimes from starvation (no food to satiation (excess food. Algal cell concentration and chlorophyll levels were used to reflect phytoplankton conditions in nature for oligotrophic waters (0-100 cells ml(-1; 0-0.01 μg chl a L(-1, natural background levels of nutrients on the Great Barrier Reef (GBR (1,000-10,000 cells ml(-1; 0.1-1.0 μg chl a L(-1, and enhanced eutrophic conditions following runoff events (100,000 cells ml(-1; 10 μg chl a L(-1. We determine how these food levels affected larval growth and survival, and the metamorphic link between larval experience and juvenile quality (size in experiments where food ration per larvae was carefully controlled. Phytoplankton levels of 1 μg chl a L(-1, close to background levels for some reefs on the GBR and following flood events, were optimal for larval success. Development was less successful above and below this food treatment. Enhanced larval performance at 1 μg chl a L(-1 provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks.

  14. Larval Starvation to Satiation: Influence of Nutrient Regime on the Success of Acanthaster planci

    Science.gov (United States)

    Wolfe, Kennedy; Graba-Landry, Alexia; Dworjanyn, Symon A.; Byrne, Maria

    2015-01-01

    High density populations of the crown-of-thorns seastar, Acanthaster planci, are a major contributor to the decline of coral reefs, however the causes behind periodic outbreaks of this species are not understood. The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth. The larval resilience hypothesis suggests that A. planci larvae naturally thrive in tropical oligotrophic waters. Both hypotheses remain to be tested empirically. We raised A. planci larvae in a range of food regimes from starvation (no food) to satiation (excess food). Algal cell concentration and chlorophyll levels were used to reflect phytoplankton conditions in nature for oligotrophic waters (0-100 cells ml-1; 0-0.01 μg chl a L-1), natural background levels of nutrients on the Great Barrier Reef (GBR) (1,000-10,000 cells ml-1; 0.1-1.0 μg chl a L-1), and enhanced eutrophic conditions following runoff events (100,000 cells ml-1; 10 μg chl a L-1). We determine how these food levels affected larval growth and survival, and the metamorphic link between larval experience and juvenile quality (size) in experiments where food ration per larvae was carefully controlled. Phytoplankton levels of 1 μg chl a L-1, close to background levels for some reefs on the GBR and following flood events, were optimal for larval success. Development was less successful above and below this food treatment. Enhanced larval performance at 1 μg chl a L-1 provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks. PMID:25790074

  15. Effect of swamp cultivation on distribution of anopheline larval habitats in Western Kenya

    Science.gov (United States)

    Omukunda, Elizabeth; Githeko, Andrew; Ndong’a, Millicent F.; Mushinzimana, Emmanuel; Yan, Guiyun

    2013-01-01

    Background & objective Malaria resurgence in highland regions of East Africa has been on increase. The spatio-temporal distribution of larval habitats of malaria vectors determines the distribution of adult vectors, hence, disease transmission. Vector’s ecology is necessary for strategic vector control through effective plan for source reduction. Mapping of the larval habitats is necessary for targeted control measures. The purpose of this study is to assess and compare the spatial and seasonal variations in anopheline larval habitats in Western Kenya. Methods A comparative study was conducted on spatial distribution of GPS geo-located anopheline larval habitats in relation to highland and lowland environments. Land use types were categorized and all potential aquatic habitats of malaria vectors were examined in February, May, August and November 2004. Data analyses were performed using SAS JMP software. Results & discussion Results showed a higher percentage of Anopheles gambiae s.s. (70.9%) than An. Funestus (29.1%) in highland. In the lowland, An. gambiae s.l. comprised 60.1% while An. funestus represented 39.9%. The distribution of larval breeding is confined to the valley bottom in the highland while it was dispersed in the lowland. Land use type influenced the occurrence of positive breeding habitats in the highland. In the lowland, distribution was due to seasonality. We found high proportion of potential and positive breeding sites in cultivated swamps and farmlands at the highland site. These results suggest that swamp cultivation increases the availability and suitability of larval breeding habitats of malaria vectors, thus malaria transmission in the Western Kenya highlands environment. PMID:22898476

  16. Larval green and white sturgeon swimming performance in relation to water-diversion flows.

    Science.gov (United States)

    Verhille, Christine E; Poletto, Jamilynn B; Cocherell, Dennis E; DeCourten, Bethany; Baird, Sarah; Cech, Joseph J; Fangue, Nann A

    2014-01-01

    Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento-San Joaquin watershed, making them logical species to examine vulnerability to entrainment by altered water flows. The risk of larval sturgeon entrainment is influenced by the ontogeny of swimming capacity and dispersal timing and their interactions with water-diversion structure operations. Therefore, the aim of this study was to describe and compare the ontogeny and allometry of larval green and white sturgeon swimming capacities until completion of metamorphosis into juveniles. Despite the faster growth rates and eventual larger size of larval white sturgeon, green sturgeon critical swimming velocities remained consistently, though modestly, greater than those of white sturgeon throughout the larval life stage. Although behavioural interactions with water-diversion structures are also important considerations, regarding swimming capacity, Sacramento-San Joaquin sturgeons are most vulnerable to entrainment in February-May, when white sturgeon early larvae are in the middle Sacramento River, and April-May, when green sturgeon early larvae are in the upper river. Green sturgeon migrating downstream to the estuary and bays in October-November are also susceptible to entrainment due to their movements combined with seasonal declines in their swimming capacity. An additional inter-species comparison of the allometric relationship between critical swimming velocities and total length with several sturgeon species found throughout the world suggests a similar ontogeny of swimming capacity with growth. Therefore, although dispersal and behaviour differ among river systems and sturgeon species, similar recommendations are applicable

  17. Hox C6 expression during development and regeneration of forelimbs in larval Notophthalmus viridescens.

    Science.gov (United States)

    Khan, P A; Tsilfidis, C; Liversage, R A

    1999-06-01

    A central theme concerning the epimorphic regenerative potential of urodele amphibian appendages is that limb regeneration in the adult parallels larval limb development. Results of previous research have led to the suggestion that homeobox containing genes are "re-expressed" during the epimorphic regeneration of forelimbs of adult Notophthalmus viridescens in patterns which retrace larval limb development. However, to date no literature exists concerning expression patterns of any homeobox containing genes during larval development of this species. The lack of such information has been a hindrance in exploring the similarities as well as differences which exist between limb regeneration in adults and limb development in larvae. Here we report the first such results of the localization of Hox C6 (formerly, NvHBox-1) in developing and regenerating forelimbs of N. viridescens larvae as demonstrated by whole-mount in situ hybridization. Inasmuch as the pattern of Hox C6 expression is similar in developing forelimb buds of larvae and epimorphically regenerating forelimb blastemata of both adults and larvae, our results support the paradigm that epimorphic regeneration in adult newts parallels larval forelimb development. However, in contrast with observations which document the presence of Hox C6 in both intact, as well as regenerating hindlimbs and tails of adult newts, our results reveal no such Hox C6 expression during larval development of hindlimbs or the tail. As such, our findings indicate that critical differences in larval hindlimb and tail development versus adult expression patterns of this gene in these two appendages may be due primarily to differences in gene regulation as opposed to gene function. Thus, the apparent ability of urodeles to regulate genes in such a highly co-ordinated fashion so as to replace lost, differentiated, appendicular structures in adult animals may assist, at least in part, in better elucidating the phenomenon of epimorphic

  18. Larval green and white sturgeon swimming performance in relation to water-diversion flows

    Science.gov (United States)

    Verhille, Christine E.; Poletto, Jamilynn B.; Cocherell, Dennis E.; DeCourten, Bethany; Baird, Sarah; Cech, Joseph J.; Fangue, Nann A.

    2014-01-01

    Little is known of the swimming capacities of larval sturgeons, despite global population declines in many species due in part to fragmentation of their spawning and rearing habitats by man-made water-diversion structures. Larval green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) inhabit the highly altered Sacramento–San Joaquin watershed, making them logical species to examine vulnerability to entrainment by altered water flows. The risk of larval sturgeon entrainment is influenced by the ontogeny of swimming capacity and dispersal timing and their interactions with water-diversion structure operations. Therefore, the aim of this study was to describe and compare the ontogeny and allometry of larval green and white sturgeon swimming capacities until completion of metamorphosis into juveniles. Despite the faster growth rates and eventual larger size of larval white sturgeon, green sturgeon critical swimming velocities remained consistently, though modestly, greater than those of white sturgeon throughout the larval life stage. Although behavioural interactions with water-diversion structures are also important considerations, regarding swimming capacity, Sacramento–San Joaquin sturgeons are most vulnerable to entrainment in February–May, when white sturgeon early larvae are in the middle Sacramento River, and April–May, when green sturgeon early larvae are in the upper river. Green sturgeon migrating downstream to the estuary and bays in October–November are also susceptible to entrainment due to their movements combined with seasonal declines in their swimming capacity. An additional inter-species comparison of the allometric relationship between critical swimming velocities and total length with several sturgeon species found throughout the world suggests a similar ontogeny of swimming capacity with growth. Therefore, although dispersal and behaviour differ among river systems and sturgeon species, similar recommendations are

  19. Tribolium castaneum larval gut transcriptome and proteome: A resource for the study of the coleopteran gut.

    Science.gov (United States)

    Morris, Kaley; Lorenzen, Marcé D; Hiromasa, Yasuaki; Tomich, John M; Oppert, Cris; Elpidina, Elena N; Vinokurov, Konstantin; Jurat-Fuentes, Juan Luis; Fabrick, Jeff; Oppert, Brenda

    2009-08-01

    Tribolium castaneum is an important agricultural pest and an advanced genetic model for coleopteran insects. We have taken advantage of the recently acquired T. castaneum genome to identify T. castaneum genes and proteins in one of the more critical environmental interfaces of the insect, the larval alimentary tract. Genetic transcripts isolated from the T. castaneum larval gut were labeled and hybridized to a custom array containing oligonucleotides from predicted genes in the T. castaneum genome. Through a ranking procedure based on relative labeling intensity, we found that approximately 17.6% of the genes represented in the array were predicted to be highly expressed in gut tissue. Several genes were selected to compare relative expression levels in larval gut, head, or carcass tissues using quantitative real-time PCR, and expression levels were, with few exceptions, consistent with the gut rankings. In parallel with the microarrays, proteins extracted from the T. castaneum larval gut were subjected to proteomic analysis. Two-dimensional electrophoretic analysis combined with MALDI-TOF resulted in the identification of 37 of 88 selected protein samples. As an alternative strategy, one-dimensional electrophoretic separation of T. castaneum larval gut proteins followed by two-dimensional nano-HPLC and ESI-MS/MS resulted in the identification of 98 proteins. A comparison of the proteomic studies indicated that 16 proteins were commonly identified in both, whereas 80 proteins from the proteomic analyses corresponded to genes with gut rankings indicative of high expression in the microarray analysis. These data serve as a resource of T. castaneum transcripts and proteins in the larval gut and provide the basis for comparative transcriptomic and proteomic studies related to the gut of coleopteran insects.

  20. PENGENDALIAN HAMA PADA TANAMAN KUBIS DENGAN SISTEM TANAM TUMPANGSARI

    Directory of Open Access Journals (Sweden)

    Seto Pandu Kristanto

    2013-08-01

    Full Text Available [ENGLISH]The research of pest control at cabbage plant by inter cropping system was done at Semboro village, Semboro town, Jember Regency. The aim of this research is to find out the most effective inter cropping system to overcome the cabbage plant’s pest problem. This research uses randomized block design (RBD with six treatments and each treatment is repeated five times. The treatments are planting monoculture cabbage, inter cropping cabbage with chili, inter cropping cabbage with marigold, inter cropping cabbage with sweet basil, inter cropping cabbage with eggplant, and inter cropping cabbage with tomato. The results shows that none of the treatments are sufficienly effective to reduce the population of both caterpillar pest, Crociodolomia binotalis or Plutella xylostella. The average population of Crociodolomia binotalis at cabbage with sweet basil’s inter cropping is lower than monoculture cabbage that is 0,89 tail/plant. The average population of Plutella xylostella for each treatment did not give a substantial different. The inter cropping of cabbage with sweet basil produces the highest weight per crop, that is 1,11 Kg/krop with grade II crop quality. Keywords: Cabbage; Crocidolomia binotalis; Plutella xylostella; inter cropping  [INDONESIAN] Penelitian pengendalian hama pada kubis dengan sistem tanam tumpangsari dilakukan di desa Semboro Kecamatan Semboro, Kabupaten Jember. Tujuan dari penelitian ini untuk mengetahui jenis tumpangsari yang efektif dalam mengendalikan hama tanaman kubis. Rancangan yang dipergunakan dalam penelitian yaitu Rancangan Acak Kelompok (RAK dengan enam perlakuan dan diulang sebanyak lima kali. Perlakuan yang digunakan yaitu penanaman kubis monokultur, kubis tumpangsari dengan cabai rawit, kubis tumpangsari dengan kenikir, kubis tumpangsari dengan selasih, kubis tumpangsari dengan terung, dan kubis tumpangsari dengan tomat. Hasil penelitian menunjukkan bahwa masing-masing perlakuan tidak efektif dalam

  1. The larval development of Pilumnoides hassleri (Decapoda: Brachyura: Pilumnoididae reared in the laboratory, with a review of pilumnoidid systematics using larval characters

    Directory of Open Access Journals (Sweden)

    Tomás A. Luppi

    2010-03-01

    Full Text Available The genus Pilumnoides is an interesting taxon because its systematic position, based on adult characters, remains unclear. These xanthoid crabs have been related to the Carpiliidae, Goneplacidae and Eriphioidea. P. hassleri A. Milne Edwards, 1880 lives in Brazilian, Uruguayan and Argentinian coasts as far south as the Magellan Strait (southwestern Atlantic. Larvae of P. hassleri from females collected in the harbour of Mar del Plata were reared in the laboratory from zoea I to megalopa and the first larval stage, and described. The species passed through 5 zoeal stages and a megalopa. Larval characters were compared with the previous description of larvae from the southeastern Pacific species P. perlatus and with species of Carpilius, Goneplax and Eriphia in order to review the relationships between these taxa.

  2. Development of the larval anterior neurogenic domains of Terebratalia transversa (Brachiopoda provides insights into the diversification of larval apical organs and the spiralian nervous system

    Directory of Open Access Journals (Sweden)

    Santagata Scott

    2012-01-01

    Full Text Available Abstract Background Larval features such as the apical organ, apical ciliary tuft, and ciliated bands often complicate the evaluation of hypotheses regarding the origin of the adult bilaterian nervous system. Understanding how neurogenic domains form within the bilaterian head and larval apical organ requires expression data from animals that exhibit aspects of both centralized and diffuse nervous systems at different life history stages. Here, we describe the expression of eight neural-related genes during the larval development of the brachiopod, Terebratalia transversa. Results Radially symmetric gastrulae broadly express Tt-Six3/6 and Tt-hbn in the animal cap ectoderm. Tt-NK2.1 and Tt-otp are restricted to a central subset of these cells, and Tt-fez and Tt-FoxQ2 expression domains are already asymmetric at this stage. As gastrulation proceeds, the spatial expression of these genes is split between two anterior ectodermal domains, a more dorsal region comprised of Tt-Six3/6, Tt-fez, Tt-FoxQ2, and Tt-otp expression domains, and an anterior ventral domain demarcated by Tt-hbn and Tt-NK2.1 expression. More posteriorly, the latter domains are bordered by Tt-FoxG expression in the region of the transverse ciliated band. Tt-synaptotagmin 1 is expressed throughout the anterior neural ectoderm. All genes are expressed late into larval development. The basiepithelial larval nervous system includes three neurogenic domains comprised of the more dorsal apical organ and a ventral cell cluster in the apical lobe as well as a mid-ventral band of neurons in the mantle lobe. Tt-otp is the only gene expressed in numerous flask-shaped cells of the apical organ and in a subset of neurons in the mantle lobe. Conclusions Our expression data for Tt-Six3/6, Tt-FoxQ2, and Tt-otp confirm some aspects of bilaterian-wide conservation of spatial partitioning within anterior neurogenic domains and also suggest a common origin for central otp-positive cell types within

  3. Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances

    DEFF Research Database (Denmark)

    Wollenberger, Leah; Breitholtz, M.; Kusk, Kresten Ole

    2003-01-01

    ketone) and 2.5 mg/l (Tonalide(TM)). Since, the synthetic musks strongly inhibited larval development in A. tonsa at low nominal concentrations, they should be considered as very toxic. The larval development test with A. tonsa is able to provide important aquatic toxicity data for the evaluation...... of synthetic musks, for which there is little published ecotoxicological information available regarding Crustacea. It is suggested that subchronic and chronic copepod toxicity tests should be used more frequently for risk assessment of environmental pollutants. (C) 2002 Elsevier Science B.V. All rights...

  4. Comparison of two versions of larval development test to detect anthelmintic resistance in Haemonchus contortus.

    Science.gov (United States)

    Várady, Marián; Corba, Július; Letková, Valéria; Kovác, Gabriel

    2009-03-23

    Larval development (LDT) and micro-agar larval development tests (MALDT) were used to compare the reliability and sensitivity of two methods for detecting anthelmintic resistance in Haemonchus contortus. The tests were conducted using three resistant and four susceptible isolates of H. contortus. Both versions of the tests provided comparable results with regard to the characterization of benzimidazole and levamisole susceptibility but neither test was sufficiently sensitive to discrimination between an ivermectin (IVM) susceptible and an IVM resistant isolate. Each test has its own merits with the LDT having the advantage of being less time-consuming.

  5. Environmental characteristics of anopheline mosquito larval habitats in a malaria endemic area in Iran

    Institute of Scientific and Technical Information of China (English)

    Moussa Soleimani-Ahmadi; Hassan Vatandoost; Ahmad-Ali Hanafi-Bojd; Mehdi Zare; Reza Safari; Abdolrasul Mojahedi; Fatemeh Poorahmad-Garbandi

    2013-01-01

    Objective: To determine the effects of environmental parameters of larval habitats on distribution and abundance of anopheline mosquitoes in Rudan county of Iran. Methods: This cross-sectional study was conducted during the mosquito breeding season from February 2010 to October 2011. The anopheline larvae were collected using the standard dipping method. The specimens were identified using a morphological-based key. Simultaneously with larval collection, environmental parameters of the larval habitats including water current and turbidity, sunlight situation, and substrate type of habitats were recorded. Water samples were taken from breeding sites during larval collection. Before collection of samples, the water temperature was measured. The water samples were analysed for turbidity, conductivity, total alkalinity, total dissolved solid, pH and ions including chloride, sulphate, calcium, and magnesium. Statistical correlation analysis and ANOVA test were used to analyze the association between environmental parameters and larval mosquito abundance. Results: In total 2 973 larvae of the genus Anopheles were collected from 25 larval habitats and identified using morphological characters. They comprised of six species:An. dthali turkhudi (3.30%), and An. apoci (1.14%). The most abundant species was An. dthali which were collected from all of the study areas. Larvae of two malaria vectors, An. dthali and An. stephensi, co-existed and collected in a wide range of habitats with different physico-chemical parameters. The most common larval habitats were man-made sites such as sand mining pools with clean and still water. The anopheline mosquitoes also preferred permanent habitats in sunlight with sandy substrates. The results indicated that there was a significant relationship between mean physico-chemical parameters such as water temperature, conductivity, total alkalinity, sulphate, chloride, and mosquito distribution and abundance. Conclusions: The results of this

  6. Biosurgery: use of larvae of necrophage insects in wound healing. The larval therapy

    Directory of Open Access Journals (Sweden)

    Magda Carolina Sánchez

    2004-12-01

    Full Text Available Larval therapy is a technique that allows the useof larva of some diptera species on chronicwounds or localized infected focuses, in order topromote the affected tissue restoration. Thetreatment velocity and efficacy, with almost nohealthy tissue loses during the process, havemade larval therapy (sometimes calledbiosurgery a viable alternative for healingwounds associated with entities as diabetic foot,venous ulcers, cutaneous chronic ulcers andburns, and some benign tumors, abscesses andosteomyelitis.Although modern medicine has been, in manycases, reticent on the application of this kind oftherapies, events as antibiotic resistance andalterations in cicatrization process in chronicwounds, have modified the respective initialpoint of view of many doctors.

  7. Larval trophodynamics, turbulence, and drift on Georges Bank : A sensitivity analysis of cod and haddock

    DEFF Research Database (Denmark)

    Werner, F.E.; MacKenzie, Brian; Perry, R.I.

    2001-01-01

    Using an individual-based model approach we consider trophodynamic effects on the growth and survival of larval cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank during late winter/early spring. These studies represent an extension of results described in Werner et al. (1996...... be an important input to larval growth and survival models. The inclusion of turbulence in determining the position of passive larvae in the water column allows the larvae to sample the entire water column, contributing to a decrease in the variance of the size of the larvae over time. The ability of larvae...

  8. A note on the population genetic consequences of delayed larval development in insects

    Directory of Open Access Journals (Sweden)

    Marcos Mattoso de Salles

    2013-01-01

    Full Text Available Observations by Dobzhansky's group in the 1940s suggesting that the presence of recessive genotypes could account for lower larval developmental rates in Drosophila melanogaster were not confirmed at the time and all subsequent investigations on this subject focused on the analysis of ecological models based on competition among pre-adult individuals. However, a paper published in this journal in 1991 eventually confirmed the finding made by Dobzhansky and his co-workers. In this report, we provide a theoretical analysis of the population genetic effects of a delay in the rate of larval development produced by such a genetic mechanism.

  9. Larval development of Austinixa bragantina (Crustacea: Brachyura: Pinnotheridae reared in the laboratory

    Directory of Open Access Journals (Sweden)

    Jô de Farias Lima

    2009-03-01

    Full Text Available The zoeal and megalopal stages of Austinixa bragantina Coelho, 2005, a small pinnotherid crab found in association with ghost shrimps Callichirus major (Say, 1818 and Lepidophthalmus siriboia Felder & Rodrigues, 1993 in the northeastern region of the state of Pará, Brazil, were reared in the laboratory from hatching to the megalopal stage. The duration of the larval period from hatching to megalopa was 28 days and the mean of duration for each larval stage was 6, 5, 5, 6, and 6 days, respectively. In the present study, the zoeal and megalopal stages are described and illustrated in detail.

  10. FACTORES QUE AFECTAN LOS PATRONES DE DISTRIBUCION DEL MODO DE DESARROLLO LARVAL EN INVERTEBRADOS MARINOS

    OpenAIRE

    PAPPALARDO, MARIA PAULA

    2013-01-01

    El modo de desarrollo larval de los invertebrados marinos es un atributo importante que afecta las tasas de dispersión, la longevidad de las especies y las tasas macroevolutivas. Los modos de desarrollo larval no se distribuyen en forma homogénea en el océano, por ende, es importante identificar y entender los factores que afectan esta distribución y su influencia en los patrones de diversidad. El objetivo general de esta tesis es entender los factores que afectan la distribución de los mo...

  11. ROLE OF DRAGONFLY (Brachytron pratense NYMPH AS A BIOCONTROL AGENT OF LARVAL MOSQUITOES

    Directory of Open Access Journals (Sweden)

    G. Chandra

    2012-10-01

    Full Text Available The failure of traditional vector control operations through chemical insecticides renewed interest in biological control method. In the present study Dragonfly (Brachytron pratense nymph has been proved to be a strong biocontrol agent of Anopheles suhpictus larvae in the laboratory condition. Average daily larval feeding rate of B. pratense nymph decreased when the search area was increased. Feeding rate increased when prey density was increased. In the field conditions also, B. pratense played very effective role as predator of different species of larval mosquitoes.

  12. ROLE OF DRAGONFLY (Brachytron pratense NYMPH AS A BIOCONTROL AGENT OF LARVAL MOSQUITOES

    Directory of Open Access Journals (Sweden)

    G. Chandra

    2012-10-01

    Full Text Available The failure of traditional vector control operations through chemical insecticides renewed interest in biological control method. In the present study Dragonfly (Brachytron pratense nymph has been proved to be a strong biocontrol agent of Anopheles suhpictus larvae in the laboratory condition. Average daily larval feeding rate of B. pratense nymph decreased when the search area was increased. Feeding rate increased when prey density was increased. In the field conditions also, B. pratense played very effective role as predator of different species of larval mosquitoes.

  13. Process-based models of feeding and prey selection in larval fish

    DEFF Research Database (Denmark)

    Fiksen, O.; MacKenzie, Brian

    2002-01-01

    rates and prey selection in larval cod. Observed pursuit times of larvae are long and approach velocity slow enough to avoid an escape response from prey, but too short to avoid loss of prey at high turbulence levels. The pause-travel search mode is predicted to promote ingestion of larger prey than...... jig dry wt l(-1). The spatio-temporal fluctuation of turbulence (tidal cycle) and light (sun height) over the bank generates complex structure in the patterns of food intake of larval fish, with different patterns emerging for small and large larvae....

  14. Response of coccinellid larvae to conspecific and heterospecific larval tracks: a mechanism that reduces cannibalism and intraguild predation.

    Science.gov (United States)

    Meisner, Matthew H; Harmon, Jason P; Ives, Anthony R

    2011-02-01

    Cannibalism, where one species feeds on individuals of its own species, and intraguild predation (IGP), where a predator feeds on other predatory species, can both pose significant threats to natural enemies and interfere with their biological control of pests. Behavioral mechanisms to avoid these threats, however, could help maintain superior pest control. Here, we ask whether larvae of Coccinella septempunctata (Coleoptera: Coccinellidae) and Harmonia axyridis (Coleoptera: Coccinellidae) respond to larval tracks deposited by the other and whether this behavioral response reduces the threat of cannibalism and IGP. In petri dish experiments, we show that both H. axyridis and C. septempunctata avoid foraging in areas with conspecific larval tracks. Using a method of preventing larvae from depositing tracks, we then demonstrate that the frequency of cannibalism is greater for both species when larvae are prevented from depositing tracks compared with when the tracks are deposited. For multi-species interactions we show in petri dish experiments that C. septempunctata avoids H. axyridis larval tracks but H. axyridis does not avoid C. septempunctata larval tracks, demonstrating an asymmetry in response to larval tracks that parallels the asymmetry in aggressiveness between these species as intraguild predators. On single plants, we show that the presence of H. axyridis larval tracks reduces the risk of IGP by H. axyridis on C. septempunctata. Our study suggests that larval tracks can be used in more ways than previously described, in this case by changing coccinellid larval behavior in a way that reduces cannibalism and IGP.

  15. The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees

    Science.gov (United States)

    In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diet are often complex and may interact with one another, necessitating the use of a geometric framework for und...

  16. Effect of Larval Competition on Extrinsic Incubation Period and Vectorial Capacity of Aedes albopictus for Dengue Virus.

    Science.gov (United States)

    Bara, Jeffrey; Rapti, Zoi; Cáceres, Carla E; Muturi, Ephantus J

    2015-01-01

    Despite the growing awareness that larval competition can influence adult mosquito life history traits including susceptibility to pathogens, the net effect of larval competition on human risk of exposure to mosquito-borne pathogens remains poorly understood. We examined how intraspecific larval competition affects dengue-2 virus (DENV-2) extrinsic incubation period and vectorial capacity of its natural vector Aedes albopictus. Adult Ae. albopictus from low and high-larval density conditions were orally challenged with DENV-2 and then assayed for virus infection and dissemination rates following a 6, 9, or 12-day incubation period using real-time quantitative reverse transcription PCR. We then modeled the effect of larval competition on vectorial capacity using parameter estimates obtained from peer-reviewed field and laboratory studies. Larval competition resulted in significantly longer development times, lower emergence rates, and smaller adults, but did not significantly affect the extrinsic incubation period of DENV-2 in Ae. albopictus. Our vectorial capacity models suggest that the effect of larval competition on adult mosquito longevity likely has a greater influence on vectorial capacity relative to any competition-induced changes in vector competence. Furthermore, we found that large increases in the viral dissemination rate may be necessary to compensate for small competition-induced reductions in daily survivorship. Our results indicate that mosquito populations that experience stress from larval competition are likely to have a reduced vectorial capacity, even when susceptibility to pathogens is enhanced.

  17. The influence of competition between foragers on clutch size decisions in an insect parasitoid with scramble larval competition

    NARCIS (Netherlands)

    Visser, M.E.

    1996-01-01

    The effect of competition between ovipositing females on their clutch size decisions is studied in animals that lay their eggs in discrete units of larval food (hosts). In such species the effect of competition depends on the form of the larval competition within such units. In insect parasitoids, t

  18. Larval growth in the dominant polychaete Polydora ciliata is food-limited in a eutrophic Danish estuary (Isefjord)

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Almeda, Rodrigo; Fotel, Frank Lech;

    2010-01-01

    Food limitation in larval growth of the spionid polychaete Polydora ciliata was examined in a typical eutrophic estuary, Isefjord, in Denmark. In the field, food availability and the energetic requirements of the P. ciliata larval population were measured during 2 different periods in 2004 and 20...

  19. Immunocytochemistry and metamorphic fate of the larval nervous system of Triphyllozoon mucronatum (Ectoprocta: Gymnolaemata: Cheilostomata)

    DEFF Research Database (Denmark)

    Wanninger, Andreas; Koop, Demian; Degnan, Bernard M.

    2005-01-01

    The development of gymnolaemate Ectoprocta includes a larval stage of either the coronate or the cyphonautes type. Herein, we provide the first description of the larval neural anatomy of a coronate larva using immunocytochemical methods. We used antibodies against the neurotransmitters serotonin...

  20. The influence of competition between foragers on clutch size decisions in an insect parasitoid with scramble larval competition

    NARCIS (Netherlands)

    Visser, M.E.

    1996-01-01

    The effect of competition between ovipositing females on their clutch size decisions is studied in animals that lay their eggs in discrete units of larval food (hosts). In such species the effect of competition depends on the form of the larval competition within such units. In insect parasitoids,

  1. Design, synthesis and insecticidal evaluation of aryloxy dihalopropene derivatives.

    Science.gov (United States)

    Yang, Ji-Chun; Li, Miao; Wu, Qiao; Liu, Chang-Ling; Chang, Xiu-Hui

    2016-02-01

    Plutella xylostella (P. xylostella) is a highly migratory, cosmopolitan species and one of the most important pest of cruciferous crops worldwide. Pyridalyl as a novel class of insecticides has good efficacy against P. xylostella. On the basis of the commercial insecticide pyridalyl, a series of new aryloxy dihalopropene derivatives were designed and synthesized by using Intermediate Derivatization Methods. Their chemical structures were confirmed by (1)H NMR, high-resolution mass spectrum (HRMS), and single-crystal X-ray diffraction analysis. The insecticidal activities of the new compounds against P. xylostella were evaluated. The results of bioassays indicated that most of the compounds showed moderate to high activities at the tested concentration, especially compounds 10e and 10g displayed more than 75% insecticidal activity against P. xylostella at 6.25mg/L, while pyridalyl showed 50% insecticidal activity at the same concentration. The field trials result of the insecticidal activities showed that compound 10e as a 10% emulsifiable concentrate (EC) was effective in the control of P. xylostella at 75-150g a.i./ha, and the mortality of P. xylostella for treatment with compound 10e at 75g a.i./ha was equivalent to pyridalyl at 105g a.i./ha.

  2. Temperature dependent larval occurrence and spat settlement of the invasive brackish water bivalve

    NARCIS (Netherlands)

    van der Gaag, M.; van der Velde, G.; Wijnhoven, S.; Rajagopal, S.

    2014-01-01

    Mytilopsis leucophaeata, an invasive bivalve species, causes fouling problems by settling on submerged constructions and in cooling water circuits in brackish water. To predict spat fall we studied the larval occurrence and settlement of this species in the brackish Noordzeekanaal canal in the Nethe

  3. A larval hunger signal in the bumblebee Bombus terrestris

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Duchateau, Marie-Jose

    2006-01-01

    Larvae of Bombus terrestris, a pollen-storing bumblebee, are dependent on progressive provisioning by workers. We test the hypothesis that larval cuticular chemicals can act as a hunger signal. We first show with a new classical conditioning experiment, using a Y-shaped tube, that workers can...

  4. Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.

    Directory of Open Access Journals (Sweden)

    Laith Yakob

    Full Text Available Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs. In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.

  5. Bioecology of Stenoma catenifer (Lepidoptera: Elachistidae) and associated larval parasitoids reared from Hass avocados in Guatemala.

    Science.gov (United States)

    Hoddle, Mark S; Hoddle, Christina D

    2008-06-01

    A 10-wk study of the avocado seed-feeding moth Stenoma catenifer Walsingham (Lepidoptera: Elachistidae), was conducted in a commercial 'Hass' avocado (Persea americana Miller [Lauraceae]) orchard in Guatemala. Up to 45% of fruit in the orchard were damaged by larval S. catenifer. Larval-to-adult survivorship for 1,881 S. catenifer larvae in Hass fruit was 37%, and adult sex ratio was 51% female. Four species of larval parasitoid were reared from field-collected S. catenifer larvae. The most common parasitoid reared was a gregarious Apanteles sp., which parasitized 53% of larvae and produced on average eight to nine cocoons per host. Apanteles sp. sex ratio was 47% female and 87% of parasitoids emerged successfully from cocoons. Apanteles sp. longevity was approximately equal to 1.5 d in the absence of food, and when provisioned with honey, parasitoids survived for 5-7 d. The mean number of cocoons produced by Apanteles sp. per host, and larval parasitism rates were not significantly affected by the number of S. catenifer larvae inhabiting seeds. Oviposition studies conducted with S. catenifer in the laboratory indicated that this moth lays significantly more eggs on the branch to which the fruit pedicel is attached than on avocado fruit. When given a choice between Hass and non-Hass avocados, S. catenifer lays up to 2.69 times more eggs on Hass.

  6. Hatchery manual for broodstock management and larval production of tubrot (Psetta maxima)

    NARCIS (Netherlands)

    Rurangwa, E.; Poelman, M.

    2011-01-01

    This hatchery manual is intended to provide detailed information from available published work and grey literature on turbot broodstock management and larval production. In reviewing larviculture techniques for turbot, it is notable that the major initial zoo technical advances were made in the 1980

  7. Legacy of road salt: Apparent positive larval effects counteracted by negative postmetamorphic effects in wood frogs.

    Science.gov (United States)

    Dananay, Kacey L; Krynak, Katherine L; Krynak, Timothy J; Benard, Michael F

    2015-10-01

    Road salt runoff has potentially large effects on wetland communities, but is typically investigated in short-term laboratory trials. The authors investigated effects of road salt contamination on wood frogs (Rana sylvatica) by combining a field survey with 2 separate experiments. The field survey tested whether wood frog larval traits were associated with road salt contamination in natural wetlands. As conductivity increased, wood frog larvae were less abundant, but those found were larger. In the first experiment of the present study, the authors raised larvae in outdoor artificial ponds under 4 salt concentrations and measured larval vital rates, algal biomass, and zooplankton abundance. Salt significantly increased larval growth, algal biomass, and decreased zooplankton abundance. In the second experiment, the authors raised larvae to metamorphosis in the presence and absence of salt contamination and followed resulting juvenile frogs in terrestrial pens at high and low densities. Exposure to road salt as larvae caused juvenile frogs to have greater mortality in low-density terrestrial environments, possibly because of altered energy allocation, changes in behavior, or reduced immune defenses. The present study suggests that low concentrations of road salt can have positive effects on larval growth yet negative effects on juvenile survival. These results emphasize the importance of testing for effects of contaminants acting through food webs and across multiple life stages as well as the potential for population-level consequences in natural environments.

  8. Complete Genome Sequence of the Larval Shellfish Pathogen Vibrio tubiashii Type Strain ATCC 19109.

    Science.gov (United States)

    Richards, Gary P; Needleman, David S; Watson, Michael A; Bono, James L

    2014-12-18

    Vibrio tubiashii is a larval shellfish pathogen. Here, we report the first closed genome sequence for this species (ATCC type strain 19109), which consists of two chromosomes (3,294,490 and 1,766,582 bp), two megaplasmids (251,408 and 122,808 bp), and two plasmids (57,076 and 47,973 bp).

  9. Draft Genome Sequence of the Shellfish Larval Probiotic Bacillus pumilus RI06-95.

    Science.gov (United States)

    Hamblin, Meagan; Spinard, Edward; Gomez-Chiarri, Marta; Nelson, David R; Rowley, David C

    2015-09-03

    Bacillus pumilus RI06-95 is a marine bacterium isolated in Narragansett, Rhode Island, which has shown probiotic activity against marine pathogens in larval shellfish. We report the genome of B. pumilus RI06-95, which provides insight into the microbe's probiotic ability and may be used in future studies of the probiotic mechanism.

  10. Emergence flux declines disproportionately to larval density along a stream metals gradient.

    Science.gov (United States)

    Schmidt, Travis S; Kraus, Johanna M; Walters, David M; Wanty, Richard B

    2013-08-01

    Effects of contaminants on adult aquatic insect emergence are less well understood than effects on insect larvae. We compared responses of larval density and adult emergence along a metal contamination gradient. Nonlinear threshold responses were generally observed for larvae and emergers. Larval densities decreased significantly at low metal concentrations but precipitously at concentrations of metal mixtures above aquatic life criteria (cumulative criterion accumulation ratio (CCAR) ≥ 1). In contrast, adult emergence declined precipitously at low metal concentrations (CCAR ≤ 1), followed by a modest decline above this threshold. Adult emergence was a more sensitive indicator of the effect of low metals concentrations on aquatic insect communities compared to larvae, presumably because emergence is limited by a combination of larval survival and other factors limiting successful emergence. Thus effects of exposure to larvae are not manifest until later in life (during metamorphosis and emergence). This loss in emergence reduces prey subsidies to riparian communities at concentrations considered safe for aquatic life. Our results also challenge the widely held assumption that adult emergence is a constant proportion of larval densities in all streams.

  11. Linking Planktonic Larval Abundance to Internal Bores at the Head of the Monterey Submarine Canyon.

    Science.gov (United States)

    Phelan, J.; Walter, R. K.; Steinbeck, J. R.

    2015-12-01

    Variability in the physical coastal environment can play an important role in determining the spatio-temporal variation in abundance of planktonic organisms. Combining planktonic larval abundance estimates over the course of a year with concurrent temperature and current data, this study provides empirical data linking a locally predominant internal tidal feature to patterns of biological abundance in the very nearshore environment at the head of Monterey Submarine Canyon. The physical observations indicate the presence of seasonally-variable semidiurnal internal bores that result in the pumping of cold (subthermocline) waters onto the adjacent shelf. Analysis of the larval abundance data indicates an assemblage shift from a relatively abundant shelf assemblage of larval fishes to a reduced abundance assemblage that is concurrent with the semidiurnal cold water intrusions driven by the tidal pumping. Results suggest that the tidal period pumping of subthermocline waters by internal bores dilutes or displaces shelf waters and their associated planktonic larval community. This could have important ecological implications at these scales and may also be of interest when siting industrial facilities that require seawater for cooling or desalination, as it would potentially reduce their impact on regional planktonic communities by diluting their rates of entrainment.

  12. Swimming speed of larval snail does not correlate with size and ciliary beat frequency.

    Science.gov (United States)

    Chan, Kit Yu Karen; Jiang, Houshuo; Padilla, Dianna K

    2013-01-01

    Many marine invertebrates have planktonic larvae with cilia used for both propulsion and capturing of food particles. Hence, changes in ciliary activity have implications for larval nutrition and ability to navigate the water column, which in turn affect survival and dispersal. Using high-speed high-resolution microvideography, we examined the relationship between swimming speed, velar arrangements, and ciliary beat frequency of freely swimming veliger larvae of the gastropod Crepidula fornicata over the course of larval development. Average swimming speed was greatest 6 days post hatching, suggesting a reduction in swimming speed towards settlement. At a given age, veliger larvae have highly variable speeds (0.8-4 body lengths s(-1)) that are independent of shell size. Contrary to the hypothesis that an increase in ciliary beat frequency increases work done, and therefore speed, there was no significant correlation between swimming speed and ciliary beat frequency. Instead, there are significant correlations between swimming speed and visible area of the velar lobe, and distance between centroids of velum and larval shell. These observations suggest an alternative hypothesis that, instead of modifying ciliary beat frequency, larval C. fornicata modify swimming through adjustment of velum extension or orientation. The ability to adjust velum position could influence particle capture efficiency and fluid disturbance and help promote survival in the plankton.

  13. Swimming speed of larval snail does not correlate with size and ciliary beat frequency.

    Directory of Open Access Journals (Sweden)

    Kit Yu Karen Chan

    Full Text Available Many marine invertebrates have planktonic larvae with cilia used for both propulsion and capturing of food particles. Hence, changes in ciliary activity have implications for larval nutrition and ability to navigate the water column, which in turn affect survival and dispersal. Using high-speed high-resolution microvideography, we examined the relationship between swimming speed, velar arrangements, and ciliary beat frequency of freely swimming veliger larvae of the gastropod Crepidula fornicata over the course of larval development. Average swimming speed was greatest 6 days post hatching, suggesting a reduction in swimming speed towards settlement. At a given age, veliger larvae have highly variable speeds (0.8-4 body lengths s(-1 that are independent of shell size. Contrary to the hypothesis that an increase in ciliary beat frequency increases work done, and therefore speed, there was no significant correlation between swimming speed and ciliary beat frequency. Instead, there are significant correlations between swimming speed and visible area of the velar lobe, and distance between centroids of velum and larval shell. These observations suggest an alternative hypothesis that, instead of modifying ciliary beat frequency, larval C. fornicata modify swimming through adjustment of velum extension or orientation. The ability to adjust velum position could influence particle capture efficiency and fluid disturbance and help promote survival in the plankton.

  14. Influence of food concentration, temperature and salinity on the larval development of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Kurian, J.

    Influence of food concentration (0.5, 1 and 2 x 10 sup(5) cell ml sup(-1) of Skeletonema costatum), temperature (20 and 30 degrees C) and salinity (15, 25 and 35 ppt) on the larval development of Balanus amphitrite (Cirripedia: Thoracica...

  15. The community structure of over-wintering larval and small juvenile fish in a large estuary

    DEFF Research Database (Denmark)

    Munk, Peter; Cardinale, Massimiliano; Casini, Michele

    2014-01-01

    the larval and early juvenile stages. In order to give more insight into the communities of the overwintering ichthyoplankton in estuarine areas, we examine an annual series of observations from a standard survey carried out 1992–2010. Species differences and annual variability in distributions...

  16. Properties of the Visible Light Phototaxis and UV Avoidance Behaviors in the Larval Zebrafish.

    Science.gov (United States)

    Guggiana-Nilo, Drago A; Engert, Florian

    2016-01-01

    For many organisms, color is an essential source of information from visual scenes. The larval zebrafish has the potential to be a model for the study of this topic, given its tetrachromatic retina and high dependence on vision. In this study we took a step toward understanding how the larval zebrafish might use color sensing. To this end, we used a projector-based paradigm to force a choice of a color stimulus at every turn of the larva. The stimuli used spanned most of the larval spectral range, including activation of its Ultraviolet (UV) cone, which has not been described behaviorally before. We found that zebrafish larvae swim toward visible wavelengths (>400 nm) when choosing between them and darkness, as has been reported with white light. However, when presented with UV light and darkness zebrafish show an intensity dependent avoidance behavior. This UV avoidance does not interact cooperatively with phototaxis toward longer wavelengths, but can compete against it in an intensity dependent manner. Finally, we show that the avoidance behavior depends on the presence of eyes with functional UV cones. These findings open future avenues for studying the neural circuits that underlie color sensing in the larval zebrafish.

  17. Factors associated with larval control practices in a dengue outbreak prone area.

    Science.gov (United States)

    Mohamad, Mariam; Selamat, Mohamad Ikhsan; Ismail, Zaliha

    2014-01-01

    In order to reduce the risk of dengue outbreak recurrence in a dengue outbreak prone area, the members of the community need to sustain certain behavior to prevent mosquito from breeding. Our study aims to identify the factors associated with larval control practices in this particular community. A cross-sectional study involves 322 respondents living in a dengue outbreak prone area who were interviewed using a pretested questionnaire. The level of knowledge about Aedes mosquitoes, dengue transmission, its symptoms, and personal preventive measures ranges from fair to good. The level of attitude towards preventive measures was high. However, reported level of personal larval control practices was low (33.2%). Our multiple logistic regression analysis showed that only those with a good level of attitude towards personal preventive measure and frequent attendance to health campaigns were significantly associated with the good larval control practices. We conclude that, in a dengue outbreak prone area, having a good attitude towards preventive measures and frequent participation in health campaigns are important factors to sustain practices on larval control.

  18. Correlation between pigmentation and larval settlement deterrence by Pseudoalteromonas sp. sf57.

    Science.gov (United States)

    Huang, Yi-Li; Li, Mu; Yu, Zhiliang; Qian, Pei-Yuan

    2011-03-01

    The red-pigmented marine bacterium Pseudoalteromonas sp. sf57 forms a biofilm that deters larval settlement of the tube-building polychaete Hydroides elegans. To investigate the correlation between pigmentation and larval settlement deterrence, mutants of sf57 with deficient or altered pigmentation were generated by transposon mutagenesis. Five groups of pigmented mutants were obtained, viz. white, yellow, pink, dark red, and white-to-red. The white mutant WM1, which exhibited a substantial increase in bacterial density in the biofilm, became inductive to larval settlement. The other mutants that showed a lesser increase in bacterial density in their biofilms either retained their deterrence or induced higher larval settlement rates, but did not become inductive strains. Analysis of the disrupted genes in these mutants suggests that the type II secretion pathway, the LysR transcriptional regulator, NAD(P)-binding proteins, exonuclease, pyruvate metabolism, flagella assembly, and cell membrane processes may play a role in the regulation of pigmentation in sf57.

  19. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2014-02-13

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  20. Proteomic analysis of the silkworm midgut during larval-pupal transition

    Directory of Open Access Journals (Sweden)

    M Kannan

    2016-06-01

    Full Text Available Metamorphosis is a key process in holometabolous insects since specific larval tissues, such as the midgut, the silk gland and the fat body, are remodeled into adult organs, or even disintegrate. However, the role of proteins and factors involved in the remodeling of these organs is still unclear. For this reason we undertook a proteomic study on the larval midgut of Bombyx mori to identify proteins whose expression significantly changes during larval-pupal metamorphosis and thus can have a role in this process. 2D-PAGE analysis showed upregulation or new expression of midgut proteins at 45 (pI 5.2, 29.8 (pI 6.11 and 20-kDa (pI 6-7 during the pupal stage. In addition zymogram analysis demonstrated the occurrence of protease activity at 37-kDa at the same developmental stage. By using MALDI-TOF-MS analysis the protein spots from 2D gel were identified as Hemolin, low molecular weight 30-kDa lipoproteins, HSP 20.8 and HSP 20.4, while the proteolytic band was identified as 37-kDa serine protease. The evidence herein presented suggests that the identified proteins could be involved in the immune protection during the remodeling of silkworm midgut that occurs at larval-pupal transition and represents a platform of knowledge necessary for future functional studies.